Potential Shale-Gas Resources in Utah by djh75337


									                                                                                                                                                                                                                                                                                                                                                                                                                                                Pennsylvanian Paradox
     Potential Shale-Gas                                                                                                Shale-Gas Drilling Activity                                                                                                     Mississippian Manning Canyon Shale
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    Chimney Rock Shale

      Resources in Utah                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         Massive dark gray
              by Michael D. Laine, Thomas C. Chidsey, Jr., and Craig D. Morgan,                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 or brown dolomitic
                         Utah Geological Survey, Salt Lake City, Utah                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           mudstone. Mule
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                31-K well, San Juan                          Dark gray or brown
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                County; 6099 ft.                             dolomitic silty mudstone
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             with wavy-laminated
                                          Summary                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            matrix. Mule 31-K well,
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             San Juan County; 6102 ft.
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             Massive dark gray
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             or brown dolomitic
Shale-gas reservoirs in Utah have tremendous untapped potential. These include the                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           mudstone.
Mississippian Manning Canyon Shale, Pennsylvanian Paradox Formation (Gothic,                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 Mule 31-K well,
Chimney Rock, Hovenweep, and Cane Creek shales for example), and Cretaceous                                                                                                                                                                                                                                                               Typical black organic-rich Manning Canyon Shale,                                                                                                                                                                                                                                                                                                                                   San Juan County;
Tropic and Mancos (Prairie Canyon, lower Blue Gate, and Tununk Members) Shales                                                                                                                                                                                                                                                            Soldier Canyon, Oquirrh Mountains, north-central Utah.                                                                                                                                                                                                                                                                                                                             6107 ft.
of north-central, southeastern, southern, and northeastern Utah, respectively. Shale
beds within these formations are widespread, thick, buried deeply enough to generate                                                                                                                                                                                                                                                      Hand Sample of Manning Canyon Shale
dry gas, and contain sufficient organic material and fractures to hold significant                                                                                                                                                                            Outcrop of Dark, Organic-Rich
recoverable gas reserves.                                                                                                                                                                                                                                   Manning Canyon Shale Interbedded
                                                                                                                                                                                                                                                             with Dark, Thin-Bedded Micritic
The Manning Canyon Shale is mainly claystone with interbeds of limestone,                                                                                                                                                                                   Limestone, Western Provo Canyon,
                                                                                                                                                                                                                                                                                                                                                                                                                                                                      Modified from Hite and others, 1984

sandstone, siltstone, and mudstone, and has a maximum thickness of 2000 ft. Total                                                                                                                                                                                  North-Central Utah                                                                                                                                                             Pennsylvanian Stratigraphic Chart for the Paradox Basin
organic carbon (TOC) varies from 1% to greater than 8% with type III (?) kerogen.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   Photomicrograph of dolomite that
In north-central Utah, the Manning Canyon was deeply buried by sediments in the                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      appears almost bimodal because
Pennsylvanian-Permian-aged Oquirrh basin and is therefore likely very thermally                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                SEM image overview showing
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    some of the crystals have replaced
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               general texture of dolostone
mature.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             original quartz or feldspar grains.
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               characterized by euhedral crystals
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        Some vestiges of white reflect
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               of dolomite that are about 10
Cyclic shale units in the Paradox Formation consist of thinly interbedded, black,                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         what is left of these original
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               microns wide and sparse silt.
organic-rich marine shale; dolomitic siltstone; dolomite; and anhydrite. They generally                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          terrigeneous clastics.
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               Mule 31-K well,
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         Plane-polarized light (100x).
range in thickness between 10 and 70 ft. These units contain TOC as high as 15%                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         Mule 31-K well,
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               San Juan County; 6099 ft.
with type III and mixed type II-III kerogen, are naturally fractured (usually on the crest                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 San Juan County; 6099 ft.
of anticlinal closures), and are typically often overpressured.
The Tropic Shale consists of dark–gray claystone containing thin lenses of siltstone,
very fine grained sandstone, and bentonite beds, and ranges in thickness from 500
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        SEM image overview of dolomitic/
to 825 ft. The Tropic can be divided into two units based on analysis of core from the                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  calcareous mudstone that is characterized
Escalante No. 1 well in south-central Utah: an organic-poor, 460- to 690-ft-thick, finely                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       Photomicrograph of an organic
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               Chimney Rock mudstone where                                                                                              by a wavy-laminated matrix primarily
laminated marlstone and calcareous claystone lower unit, and an organic-rich, 340-                                                                                                                                                                                                                                                                                                                                                                                                                                                Modified from Nuccio and Condon, 1996
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 terrigenous clastics are clearly                                                                                       composed of clay minerals. Closer
to 460-ft-thick, thinly interlaminated siltstone grading upward to claystone upper                                                                                                                                                                                                                                                                                                                                                        Modified from Schamel, 2006;
                                                                                                                                                                                                                                                                                                                                                                                                                                          data from Hite and others, 1984
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  Thermal Maturities (Production                               entombed in the chloritic, illitic,                                                                                      examination reveals considerable amounts
unit. The upper unit contains TOC as high as 3.9% with type II and mixed type II-III                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         and slightly smectitic matrix mud.                                                                                         of calcareous and dolomitic cements
                                                                                                                                                                                                                                                                                                                                              Modified from Swetland
                                                                                                                                                                                                                                                                                                                                                                                                                                            Distribution of TOC Values,                                          Index) at the Gothic Shale Interval                               Plane-polarized light (100x).                                                                                        admixed with laminated clay minerals.
kerogen.                                                                                                                                                                                                                                                                                                                                      and others, 1978
                                                                                                                                                                                                                                                                                                                                                                                                                                             Northern Paradox Basin
                                                                                                                                        • Planned, Drilling, or Completed Shale-Gas Well                                                                                                                                                                                                                                                                                                                                                                                                        Mule 31-K well,                                                                                         These cements reduce primary porosity that
The Mancos Shale consists of interbedded claystone, siltstone, and very fine grained                                                                                                                                                                                                                                                             Average TOC Content Values vs.                                                                                                                                                                                                       San Juan County; 6102 ft.                                                                                         mainly includes flattened intercrystalline
                                                                                                                                                                                                                                                                                                                                                 Thickness for Manning Canyon                                                                                                                                                                                                                                                                                                                           micropores between clay minerals.
sandstone. The thickness of potential shale-gas members of the Mancos ranges up to                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      Mule 31-K well, San Juan County; 6102 ft.
1500 ft. In the Uinta Basin, vitrinite reflectance at the top of the Mancos ranges from                                                                                                                                                                                                                                                           Shale & Doughnut Formation
                                                                                                                                Cretaceous Mancos Shale                            20             Delta       9472
0.65% to 1.50%; TOC is 1% to 2% with type II to mixed type II-III kerogen.
                                                                                                                          Map No.       Operator      Depth (ft.)                  21             Delta       8950
                                                                                                                                                                                                                                                                                                                                                                                                                                                 Photomicrograph of a silty dolomite bed                                                                                             Photomicrograph of a dolomite interbed
                                                                                                                              1           Questar       12,620                     22        Fidelity E & P   7650                                                                                                                                                                                                                                                                                                                                                                                                                                                                            SEM image of shale texture exhibiting weakly
                              Acknowledgments                                                                                 2        Wind River       10,500                     23     Babcock & Brown     7925
                                                                                                                                                                                                                                                                                                                                                                                                                                                    situated between Chimney Rock shale
                                                                                                                                                                                                                                                                                                                                                                                                                                                 sequences. These dolomite interbeds are
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     that is more solidly dolomitic with
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     less obvious terrigeneous material.
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              developed laminae composed of stacked and
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              crenulated clay flakes. A matrix composition
                                                                                                                              3           Questar        11539                     24         CrownQuest      6085                                                                                                                                                                                                                             reasonably common in core, and possess a                                                                                              Nonetheless, this unit again occurs
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              of mixed illite, illite/smectite, and chlorite is
Funding for this ongoing research was provided, in part, by the Unconventional                                               4        Royale Energy      11274                     25         CrownQuest      6085                                                                                                                                                                                                                           low gamma ray signature on open-hole logs.                                                                                              stratigraphically between Chimney Rock
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              probable. Carbonaceous particles (c) aligned
Onshore Program of the Research Partnership to Secure Energy for America (RPSEA),                                                                                                                                                                                                                                                                                                                                                               Because these interbeds are microporous,                                                                                             mudstone intervals. While this unit
                                                                                                                              5       Royale Energy      11322                     26         CrownQuest      5920                                                                                                                                                                                                                                                                                                                                                                                                                                                                            parallel to bedding in shale. Crenulated shapes of
                                                                                                                                                                                                                                                                                                                                                                                                                                              petrophysical recognition of such interbeds                                                                                            looks tight, one could argue that any sort
Sugar Land, Texas, for the Utah Geological Survey project titled Paleozoic Shale-                                             6          Retamco         9500                      27         CrownQuest      5875                                                                                                                                                                                                                                                                                                                                                                                                                                                                            clay flakes, irregularities introduced by diagenetic
                                                                                                                                                                                                                                                                                                                                                                                                                                            is important for understanding the influence                                                                                             of porosity/permeability combination
Gas Resources of the Colorado Plateau and Eastern Great Basin, Utah: Multiple Frontier                                                                                                                                                                   Modified from Moyle, 1958
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     might be encountered in these associated
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              cement crystals, and admixed organic particles
                                                                                                                              7       Petro-Canada      11500                      28         CrownQuest      5960                                                                                                                                                                                                                                of lithologies, other than mudstones, on
Exploration Opportunities. Support is also being provided by the Utah Geological Survey                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       all create open micropores in the heterogeneous
                                                                                                                              8           Gasco          15941                     29         CrownQuest      5883                                                                                                                                                                                                                                             potential production results.                                                                                         dolomitic examples.
(UGS).                                                                                                                                                                                                                                                         Manning Canyon Shale Stratigraphic                                                                                                                                                              Plane-polarized light (100x).                                                                                         Plane-polarized light (100x).
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              shale matrix.
                                                                                                                              9      Bill Barret Corp   19000                      30         CrownQuest      5950                                                Section, Oquirrh Mountains,                                                                                                                                                                                                                                                                                                                                                                                                 Jefferson State 4-1 well, San Juan County; 6195 ft.
                                                                                                                                                                                                                                                                                                                                                                                                                                                Mule 31-K well, San Juan County; 6107 ft.                                                                                            Mule 31-K well, San Juan County; 6113 ft.
Interpretations and several figures were selected from the following UGS open-file reports:                                  10        XTO Energy        7250                      31         CrownQuest      5880                                                     North-Central Utah
Shale-Gas Reservoirs of Utah: Survey of an Unexploited Potential Energy Resource, Open-File Report 461                       11        XTO Energy        8750                      32         CrownQuest      6375
(2005) by Steve Schamel.                                                                                                     12        XTO Energy        9500                      33        Baytex Energy    6365

Shale-Gas Resources of Utah: Assessment of Previously Undeveloped Gas Discoveries, Open-File Report 499
                                                                                                                                                                                        Mississippian Manning
                                                                                                                                                                                            Canyon Shale                                                          Manning Canyon Shale                                                                                                                                                             SEM image of shale highlighting a laminated fabric of
(2006) by Steve Schamel.                                                                                                                                                                   Bill Barrett Corp                                                                                                                                                                                                                                                                                                                                                                                                                                                           Elemental spectrum for the clay flake shown with arrow
                                                                                                                          Pennsylv anian Paradox Formation                         34                         8300                                 Relatively little is known about the gas potential of the Manning Canyon Shale.                                                                                                                 crenulated clays. Little or no silt or sand-sized material
Integrated Sequence Stratigraphic and Geochemical Resource Characterization of the Lower Mancos Shale,                                                                             35          Chief O&G      7300                                 This unit is now being investigated by the Utah Geological Survey to:                                          Modified from                                                                                                                                                                                                                                                                                        on image to the left. In addition to Si, O, and Al peaks
                                                                                                                             15      Bill Barret Corp    6483                                                                                                                                                                                                     Moyle, 1958                                                                     is observed, identifying the sample as shale rather than
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       indicative of clay, medium-sized peaks for Mg and Fe
Uinta Basin, Utah, Open-File Report 483 (2006) by Donna S. Anderson and Nicholas B. Harris.                                                                                        36             Shell       9400                                 • Identify and map the major trends for target shale intervals                                                                                                                                     mudstone. A mixture of detrital clays is most likely;
                                                                                                                             16       Petro-Canada       7588                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          suggest a chlorite composition. The K peak likely denotes
                                                                                                                                                                                   37        Petro-Canada      37                                  • Identify areas with the greatest gas potential                                               Thickness and Distribution of                                                                        the large flake (arrow) produces the spot elemental
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       illite, whereas the Ca peak could indicate intermixed illite/
Hydrocarbon Potential of Pennsylvanian Black Shale Reservoirs, Paradox Basin, Southeastern Utah by S.                        17            Delta                                                                                                                                                                                                                                                                                                   spectrum. Induced stress-release porosity is evident as
Robert Bereskin (open-file report in preparation).                                                                                                                                 38             Shell        38                                  • Characterize the geologic, geochemical, & petrophysical rock                                   Manning Canyon Shale in                                                                                                                                                                                                                                                                                            smectite. Gold peaks reflect sample coating.
                                                                                                                             18            Delta                                                                                                                                                                                                                                                                                                               elongate microfractures parallel to bedding.
                                                                                                                                                                                                                                                     properties                                                                                   Northern Utah and Correlative                                                                         Jefferson State 4-1 well, San Juan County; 6193 ft.
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       Jefferson State 4-1 well, San Juan County; 6193 ft.
The poster design was by Stevie Emerson of the UGS. James Parker, Sharon Wakefield, Sonja Heuscher,                          19       Petro-Canada        7331                                                                                     • Reduce exploration costs & drilling risk                                                     Formations in Adjacent Areas
and Cheryl Gustin of the UGS prepared the figures; Brad Wolverton of the UGS Core Research Center                                                                                                                                                  • Recommend the best practices to complete & stimulate targeted
assisted with core photography.                                                                                                                                                                                                                      shale-gas zones to reduce development costs & maximize gas

                                                                          Gothic Shale                                                                                                                     Cretaceous Tropic                                                                                                                                                                                                                                                                                                                                                              Prairie Canyon Member
                                                                                                                                                                                                           and Mancos Shales                                                                                                        Tropic Shale
                                                                                                                                               SEM image of poorly laminated
                             Dark gray dolomitic
                             mudstone showing contact                                                                                          mudstone at low magnification.
                             with overlying Ismay zone.                                                                                        Likely minerals include clays
                             Mule 31-K well,                                                                                                   (illite and possibly chlorite),
                             San Juan County; 5901 ft.                                                                                         dolomite, and quartz. Several
                                                                                                                                               pyrite framboids (arrows) are
                                                                                                                                               visible in this image.
                                                                                                                                               Jefferson State 4-1 well,
                                         Dark gray dolomitic silty                                                                             San Juan County; 6051 ft.
                                          mudstone with wavy to
                                              planar lamination.
                                                  Mule 31-K well,
                                        San Juan County; 5902 ft.
                                                                                                                                               SEM image at higher
                                                                                                                                               magnification, silt-sized calcite
                                                                                                                                               and non-ferroan dolomite grain
                                                                                                                                               replacements populate a matrix
                                                                                                                                               of wavy and crenulated clay
                                                                                                                                               flakes. The most common pores                                                                                                                                                                                                                                                                                                                                                                                                                                                                      Modified from Cole

                                                                                                                                               are intercrystalline micropores                                                                                                                                                                                                                                                                                                                                                                                                                                                                    and others, 1997.

                                  Photomicrograph of the Gothic Shale composed of                                                              between clay flakes. Jefferson                                                                                                                                                                                                                                                                                                                       Modified from Schamel 2005;                                                                                                                                                                                             Modified from Cole
                                                                                                                                                                                                                                                                                                                                                                            Modified from Doelling, 1972   Modified from Schamel, 2005.                                                             Data from White, 1999.                                                                                                                                                                                                  and Young, 1991.
                                  terrigeneous material, fossils, and clays. Mottled                                                           State 4-1 well,                                                                                                                                                                                                                                                                                                                                                                                                                      Distribution of the Prairie Canyon Member, Southeast Uinta
                                  appearance may be related to some bioturbation. In                                                           San Juan County; 6051 ft.                                                                                                                                                                                                                                    Gamma Ray Log, Tropic Shale, Escalante                                                       RockEval-Derived Hydrogen Index                                                                                                                                                 Prairie Canyon Member Lithofacies
                                  this well, the Gothic is fractured, and in this view                                                                                                                                                                                                                                       Stratigraphic Position of the Tropic Shale,                                                                                                                                                                                                                 Basin, Douglas Creek Arch, Piceance Creek Basin
                                                                                                                                                                                                                                                                                                                                                                                                            No. 1 Well, Northern Kaiparowits Plateau,                                                   (HI) Escalante No. 1 Well, Northern
                                  a subvertical fracture is composed of red-stained                                                                                                                                                                                                                                                     South Central Utah
                                  calcite. However, not all fractures in this interval are                                                                                                                                                                                                                                                                                                                              South Central Utah                                                            Kaiparowits Plateau, South Central Utah
                                  completely occluded by diagenetic minerals. Plane-                                                                                                                                                               Late Cretaceous Paleogeography                                                                                                                                                                                                                                                                                                                        Bioturbated
                                  polarized light (40x). Jefferson State 4-1 well,                                                             SEM image of mudstone
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         muddy sandstone
                                  San Juan County; 6037 ft.                                                                                    texture dominated by
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         lithofacies. 8-2-
                                                                                                                                               interlocking, subhedral                                                                                                                                                                                                                                                                                                                                                                                                                                   15-22 State of
                                                                                                                                               dolomite crystals.                                                                                                  Tropic-Tununk and Lower Blue Gate Shale                                                                                                                                 Interbedded thinly laminated,
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         Utah well, Uintah
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            lithofacies with wave-
                                                                                                                                               Porosity is likely minimal.                                                                                                                                                                                                                                                                                                                                                                                                                               County; 5425 ft.                                                                   ripple and current-
                                                                                                                                                                                                                                                                                                                                                                                                                                           graded siltstone with loadcasts
                                                                                                                                               Jefferson State 4-1 well,                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    ripple lamination.
                                                                                                                                                                                                                                                          • Zones with organic richness in excess of 2.0%                                                                                                                                  and dark gray claystone.
                                                                                                                                               San Juan County; 6070 ft.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    8-2-15-22 State of Utah
                                  Photomicrograph of the Gothic Shale at higher                                                                                                                                                                                                                                                                                                                                                            Escalante 1 well,
                                                                                                                                                                                                                                                                                                                                                                                                                                           Garfield County; 434 ft.                                                                                                                                                                                                                         well,Uintah County;
                                  magnification illustrating the mixed mineralogy/                                                                                                                                                                        • Wide distribution of these units                                                                                                                                                                                                                                                                                                                                                                                                5433 ft.
                                  grain content, the ribbonlike nature of the calcitic (red)
                                  fracture filling, and the dark material representing both                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 Sandstone-claystone
                                  carbonaceous material and pyrite. The mud matrix is                                                          SEM image of at higher                                                                                     • Thin-bedded sandstone intervals could be gas-charged where in close                                                                                                                                                                                                                                                                                  lithofacies with
                                  modestly microporous. Plane-polarized light (100x).                                                          magnification of dolomitic                                                                                   juxtaposition to organic-rich shales                                                                                                                                                                                     Graded laminated siltstone
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          lenticular lamination
                                  Jefferson State 4-1 well, San Juan County; 6037 ft.                                                          mudstone highlighting packets                                                                                                                                                                                                                                                                                                                                                                                                                                    and wave-ripple
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    lenses within very dark gray                                                                                                                                                                                   Sandstone-claystone
                                                                                                                                               of clays (preferred alignment                Modified from Cole                                                                                                                                                                                                                                                                                                                                                                                                and current-ripple
                                                                                                                                                                                            and others, 1997                                              • Potential “sweet spots” for shale gas where the rocks are sufficiently buried                                                                                                                                        laminated calcareous claystone.                                                                                                                                                                             lithofacies with lenticular
                                                                                                                                               lower left to upper right)                                                                                                                                                                                                                                                                                                                                                                                                                                    lamination. 8-2-15-
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                Escalante 1 well,                                                                                                                                                                                   lamination. 8-2-15-
                                                                                                                                               sandwiched between dolomite                                                                                                                                                                                                                                                                                                                                                                                                                                22 State of Utah well,
                                                                                                                                                                                                    Stratigraphy of the                                                                                                                                                                                                                                                                 Garfield County; 436 ft.
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         Uintah County; 5435 ft.                                                                 22 State of Utah well,
                                                                                                                                               crystals. The tightly crystalline                                                                          • Oil-prone shale intervals that are in the uppermost oil window may yield
                                                                                                                                               fabric leaves little visible
                                                                                                                                                                                                      Mancos Shale                                                                                                                                                                                                                                                                                                                                                                                                                                                                             Uintah County; 5436 ft.
                      Paradox Formation                                                                                                        microporosity.
                                                                                                                                                                                                                                                            gas in deep-burial conditions in the Uinta Basin
                                                                                                                                               Jefferson State 4-1 well,
                                                                                                                                               San Juan County; 6070 ft.
• Pennsylvanian “black shale” Gothic and Chimney Rock (as well as the
  Cane Creek and Hovenweep shales) are likely gas productive in certain
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          Tununk Shale                                                        Prairie Canyon Member
  zones.                                                                                                                                                                                                  Blue Gate Shale
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       • Lean, dominantly humic, kerogen is contained
• The porosity of all reservoirs is modest – estimated between 2 and 5%                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  in the shale interlaminated with the siltstone-
  based on testing to date.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              sandstone
• The interbedded dolomite within and bounding the mudstone sections                                                                                                                                                                                                                                                                                                   Upper high-TOC interval with dense, non-                                                                                                                                                                          Dark gray calcareous
  may be the most permeable conduit for sustained hydrocarbon                                                                                                                                                                                                                                                                                                          fissle, dark gray claystone and scattered, light                                                                                                                                                                                                                • High quartz content is likely to result in a higher
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         mudstone with silt to very
  production. Permeability is likely modest but appears best represented                                                                                                                                                                                                                                                                                               gray silt laminae and bivalve fragments. River                                                                                                                                                                    fine sand laminae and                           degree of natural fracturing than the enclosing
                                                                                                                                                                                                                                                                                                                                                                       Gas of Utah 1 well, Carbon County; 797 ft.                                                                                                                                                                                                                        claystone-mudstone rocks
  by intercrystalline porosity from euhedral to subhedral dolomite crystal                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               interbeds, and silt–filled
  aggregates.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            burrows.
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         River Gas of Utah 1 well,
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         Carbon County; 1885 ft.                       • May respond well to hydraulic fracturing
• The larger, partially filled natural fractures (filled mainly by calcite)
  could assist in providing a respectable initial potential flow especially                                                                                                                                                                                                                                                                                                        Lower high-TOC interval with dense, non-
                                                                                                  Elemental spectrum for corresponding to the area in the SEM image                                                                                                                                                                                                               fissle very dark gray claystone. River Gas of                                                                                                                                                                                                        • Porosity of the sandstone interbeds averaging 5.4%
  when the hydraulic fracturing protocol is able to access natural fracture                       above. Peaks for Si, O, Al and K likely indicate illite, whereas Ca, Mg                                                                                                                                                                                                                 Utah 1 well, Carbon County; 1175 ft.                                                                                                                                                                                                           can enhance gas storage
  occurrence. Much of this fracturing occurs in the associated dolomites,                         and O peaks denote dolomite. A likely interpretation is a diagenetic
  although not exclusively.                                                                       dolomite overprint on an illitic mudstone matrix. The small Fe peaks                                                                                                               Modified from Nuccio and others, 1992

                                                                                                  are more likely associated with clays than dolomite because the analysis                                                                                                                                                                                                                                                                                                                       Modified from Schamel 2005;                                                                                                           • Extends beneath the southeast Uinta Basin reaching
                                                                                                                                                                                             From Anderson and Harris, 2006, unpublished figure.                                         Thermal Maturities (Vitrinite                                                                                                                                                                           Data from Dumitrescu, 2002.

• The calcareous mudstones are likely productive as well, although
                                                                                                  on individual dolomite crystals shows no Fe component.
                                                                                                                                                                                                                                                                                         Reflectance) at the Top of the                                                                                                                                                                              Total Organic Carbon,                                                                                                               depths sufficient for gas generation and retention
                                                                                                  Jefferson State 4-1 well, San Juan County; 6070 ft.                                                            Isopach Map of Organic-                                                                                                                                                                                                                                                             Lower Blue Gate Shale,                                                                                                              from the gas-prone kerogen
  matrix permeability is still in the nanodarcy range. Production from                                                                                                                                                                                                                           Mancos Shale
  the mudstones is possibly related to both interstitial and desorbed gas.                                                                                                                                          Rich Mancos Shale                                                                                                                                                                                                                                                                River Gas of Utah No. 1
         References                              Lincoln, University of Nebraska, M.S.
                                                 thesis, 71 p.
                                                                                                 Fouch, T.D., Nuccio, V.F., and Chidsey,
                                                                                                 T.C., Jr., editors, Hydrocarbon and min-
                                                                                                 eral resources of the Uinta Basin, Utah
Cole, R.D., and Young, R.G., 1991, Facies    Hite, R.J., Anders, D.E., and Ging, T.G.,
    characterization and architecture of a                                                       and Colorado: Utah Geological Associa-
                                                 1984, Organic-rich source rocks of              tion Publication 20, p. 77-93.
    muddy shelf-sandstone complex: Man-          Pennsylvanian age in the Paradox Basin
    cos B interval of the Mancos Shale,          of Utah and Colorado, in Woodward,         Swetland, P.J., Clayton, J.L., and Sable, E.G.,
    northwest Colorado - northeast Utah, in      Jane, Meissner, F.F, and Clayton, J.L.,       1978, Petroleum source-bed potential
    Miall, A.D., and Tyler, N., editors, The     editors, Hydrocarbon source rocks of          of Mississippian-Pennsylvanian rocks
    three-dimensional facies architecture of     the greater Rocky Mountain region:            in parts of Montana, Idaho, Utah, and
    terrigeneous clastic sediments and its       Rocky Mountain Association of Geolo-          Colorado: Mountain Geologist, v. 14, p.
    implications for hydrocarbon discovery       gists Guidebook, p. 255-274.                  79-87.
    and recovery: Society for Sedimentary
    Geology (SEPM) Concepts in Sedimen- Moyle, R.W., 1958, Paleoecology of the Man-         White, T.S., 1999, A sequence stratigraphic
    tology and Paleontology, v. 3, p. 277-       ning Canyon Shale in central Utah:            and geochemical investigation of lower
    286.                                         Brigham Young University Research             to middle Turonian (Cretaceous) strata
                                                 Studies, v. 5, no. 7, 86 p., 7 plates.        of the Western Interior Seaway, Utah,
Cole, R.D., Young, R.G., and Willis, G.C.,
    1997, The Prairie Canyon Member, a       Nuccio, V.F., and Condon, S.M., 1996, Buri-       Colorado and western Kansas: Univer-
    new unit of the Upper Cretaceous Man-        al and thermal history of the Paradox         sity Park, Pennsylvania State University,
    cos Shale, west-central Colorado and         Basin, Utah and Colorado, and petro-          Ph.D. dissertation, 287 p.
    east-central Utah: Utah Geological Sur-      leum potential of the Middle Pennsylva-
    vey Miscellaneous Publication 97-4, 23       nian Paradox Formation, in Huffman,
    p.                                           A.C., Jr., Lund, W.R., and Godwin, L.H.,            DISCLAIMER
                                                 editors, Geology and resources of the
Doelling, H.H., and Graham, R.L., 1972,          Paradox Basin: Utah Geological Asso-       Although this product represents the work of pro-
    Southwestern Utah coal fields – Alton,       ciation Publication 25, p. 57-76.          fessional scientists, the Utah Department of Natural
    Kaparowitz Plateau and Kolob-Harmo-                                                     Resources, Utah Geological Survey, makes no war-
    ny: Utah Geological and Mineralogical    Nuccio, V.F., Schmoker, J.W., and Fouch,       ranty, expressed or implied, regarding its suitability
    Survey Monograph Series No. 1, 533 p.        T.D., 1992, Thermal maturity, porosity,    for a particular use. The Utah Department of Natu-
                                                 and lithofacies relationships applied to   ral Resources, Utah Geological Survey, shall not be
Dumitrescu, M., 2002, Organic carbon-sul-        gas generation and production in Cre-      liable under any circumstances for any direct, indi-
    fur-iron relationships in condensed in-      taceous and Tertiary low-permeability      rect, special, incidental, or consequential damages
                                                 (tight) sandstone, Uinta Basin, Utah, in   with respect to claims by users of this product.
    tervals of the Cretaceous Mancos Shale:

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