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					                                     Multilateral Investment Guarantee Agency

                                            Environmental Guidelines for

   Oil and Gas Development (Onshore)
                                              pressure reduction, gravity separation,
Industry Description and Practices            and emulsion "breaking" techniques.
                                              Gas that is produced may be used
This document addresses onshore oil           directly as fuel or as feedstock for the
and gas exploration, drilling, and            manufacture of petrochemicals. It may
production operations. Refining               also contain small amounts of sulfur
operations are covered in a separate          compounds such as mercaptans and
document. Testing, delineation and            hydrogen sulfide. Sour gas is
production drilling are integral to           sweetened by processes such as amine
hydrocarbon reservoir development.            scrubbing.
This involves the use of drilling rigs
(and associated equipment such as             Waste Characteristics
casing and tubing), large quantities of
water, and drilling muds. In the              The major environmental concerns
process, oil and gas are moved to the         associated with onshore oil and gas
surface through the well bore either          production are drilling waste fluids or
through natural means (the reservoir          muds, drilling waste solids, produced
has enough pressure to push the oil           water, and volatile organics. The
and gas to the surface) or through            drilling waste muds may be fresh-
induced pressure (by means of a pump          water gel, salt water (potassium
or other mechanism). At the surface,          chloride or sodium chloride), or oil
oil, gas, and water are separated.            invert-based systems. The oil invert
Crude oils with associated gas                mud systems may contain up to 50
containing more than 30 milligrams            percent by volume of diesel oil.
per cubic meter (mg/m3) of hydrogen              The drilling waste may contain
sulfide are normally classified as "sour      drilling muds (bentonite), bore-hole
crude". The crude oil may require             cuttings, additives (polymers, oxygen
further processing including the              scavengers, biocides, surfactants,
removal of associated gas. Oil                lubricants, diesel oil, emulsifying
produced at the wells is piped or             agents, and various other wastes that
shipped for use as feedstock in               are specifically related to the drilling
petroleum refineries.                         activities.
   Natural gas is predominantly                  The drilling waste solids, which are
methane with smaller amounts of               made up of the bottom layer of drilling
ethane, propane, butanes, pentanes,           mud sump materials, may contain drill
and heavier hydrocarbons. Gas wells           cuttings, flocculated bentonite,
produce small quantities of condensate        weighting materials and other
which may require processing.                 additives. Additional wastes from the
Separation processes generally use            drilling process include used oils,

446                                                              Oil and Gas Development (Onshore)

cementing chemicals, and toxic                COD                             180-580
   Field processing of crude oil will         Phenols                            50
generate several waste streams
                                              Cadmium                            0.7
including contaminated wastewater,
tank bottoms which may contain lead,          Chromium                           2.3
emulsions, and heavy hydrocarbon
                                              Copper                             0.4
residues which may contain
polynuclear aromatic hydrocarbons             Lead                               0.2
(PAHs). Cooling tower blowdown,
boiler water, scrubber liquids, and           Mercury                            0.1
steam production wastes are also              Nickel                             0.4
generated, as well as contaminated
soil, used oil, and spent solvents.
   Wastewaters that are generated               Major sources of air emissions
typically contain suspended solids. To       include fired equipment, vents, flares
control the growth of micro-organisms        (including those from compressor
in sour water, usually a biocide or          stations), and fugitive emissions. These
hydrogen sulfide scavenger (for              may contain volatile organic
example, sodium hypochlorite) is used        compounds (VOCs), sulfur oxides,
prior to its reinjection or disposal.        hydrogen sulfide, and nitrogen oxides.
Crude pipelines are routinely cleaned
by pigging operations which can lead         Air Emissions from Oil and Gas
to spills and to the generation of           Production
sludge containing heavy metals. Solid         Gas Production
wastes which do not contain toxics are
used as back-fill material.                      Sulfur Oxides         Less than 0.1 grams per
   The following is a characterization                                 cubic meter (g/m3) of
of the overall wastewater stream from                                  gas produced
crude processing:                                Nitrogen Oxides       10-12 g/m3 of gas
Crude Processing Wastewater
                                                 VOCs                  0.1-14 g/m3 of gas
      Parameter         Typical values                                 produced
                      milligrams per liter       Methane               0.2-10 g/m3 of gas
                            (mg/L)                                     produced
 Oil and grease         7-1,300 (200)         Oil Production

 Total organic          30-1,600 (400)           Nitrogen Oxides       3.7 grams per kilogram
 carbon                                                                (g/kg) oil produced
 Total suspended         20-400 (70)             VOCs                  3.3-26 g/kg oil
 solids (TSS)                                                          produced
 Total dissolved       30,000-200,000
 solids (TDS)             (100,000)          Pollution Prevention and Control
 Biochemical oxygen        120-340           Pollution prevention programs should
 demand (BOD5)                               focus on reducing the impacts of
                                             wastewater discharges, oil spills and
                                             soil contamination and on minimizing
                                             air emissions. Minimizing the quantity
447                                                          Oil and Gas Development (Onshore)

of discharge should be stressed.              Practice good house keeping, and
Process changes might include the           ensure that appropriate operating and
following:                                  maintenance programs are in place.
  • Maximize the use of freshwater             A reclamation and closure plan for
gel-based mud systems.                      the site is required. This plan should
  • Eliminate the use of invert (diesel     be developed early in the project and
based) muds. In case where the use of       should address the removal and
diesel-based muds is necessary, reuse       disposal of production facilities in an
the muds.                                   environmentally sensitive manner, the
  • Recycle drilling mud decant             restoration of the site, and provisions
water.                                      for any ongoing maintenance issues.
  • Prevent degradation of sweet            Where possible, progressive
wells by sulfate reducing bacteria by       restoration should be implemented.
the use of hydrogen sulfide
scavengers.                                 Target Pollution Loads
  • Select less toxic biocides, corrosion
inhibitors, and other chemicals.            Implementation of cleaner production
  • Minimize gas flaring. However,          processes and pollution prevention
flaring is preferred to venting.            measures can provide both economic
  • Store crude oil in tanks with the       and environmental benefits. In drilling
large ones (greater than 1,590 m3)          operations, the use of fresh water
having secondary (double) seals.            should be minimized by maximizing
  • Minimize and control leakage            the use of drilling mud pond decant
from tanks and pipelines.                   water. Eliminate sour gas emissions by
  • Practice corrosion prevention and       sweetening and reuse.
monitor above and below ground
tanks, vessels, pipes etc.                  Treatment Technologies
  • Remove hydrogen sulfide and
mercaptans from sour gases (releasing       Typically, air emissions of toxic
greater than 1.8 kg of reduced sulfur       organics are minimized by routing
compounds per hour) before flaring.         such vapors to recovery systems,
  • Use knock-out drums on flares to        flares, or boilers. Tail gases are
prevent condensate emissions.               scrubbed to remove sulfur
  • Regenerate spent amines and             compounds.
spent solvents or send off-site for            The decant from the drilling mud
recovery.                                   disposal sump is treated by
  • Use low nitrogen oxides (NOx)           coagulation and settling before
burners in process heaters (especially      discharge. Alternatively, the sump
in those with a design heat input of        fluids may be injected downhole into
4.2X 1010 Joules per hour).                 an approved disposal formation.
  • Provide spill prevention and               The drained and settled drilling
control measures (bunds/berms and           mud solids are disposed on land:
hard surfacing for storage tanks;           capping; mixing, burying, and
pressure relief valves; and high-level      covering; trenching; or encapsulating.
alarms).                                    Other options include land spreading,
  • Recover oil from process                land filling, incineration (for
wastewaters.                                destruction of toxic organics), or in-situ
  • Segregate storm water from              solidification/fixation.
process water.                                 Effluents from the crude process
  • Implement leak detection and            may be treated using coagulation, de-
repair programs.                            emulsification, settling, and filtration.
448                                                                Oil and Gas Development (Onshore)

Storm water is settled and if necessary,     Emissions from Oil and Gas
treated (coagulation, flocculation, and      Production (Onshore)
sedimentation) before discharge.
                                                     Parameter                Maximum value
Emission Requirements                                                      milligrams per normal
                                                                           cubic meter (mg/Nm3 )
Emission levels for the design and           VOCs (including                           20
operation of each project must be            benzene)
established through the Environmental
Assessment (EA) process, based on            Hydrogen sulfide                          30
country legislation and the Pollution        Sulfur oxides (for oil                  1,000
Prevention and Abatement Handbook as         production)
applied to local conditions. The
emission levels selected must be             Nitrogen oxides
justified in the EA and acceptable to                  Gas-fired            320 mg/Nm3 (or 86
MIGA                                                                              ng/J)
   The following guidelines present                    Oil-fired           460 mg/Nm3 (or 130
emission levels normally acceptable to                                            ng/J)
the World Bank Group in making
decisions regarding provision of             Odor                         Not offensive at the
World Bank Group assistance,                                              receptor end*
including MIGA guarantees; any
deviations from these levels must be         *H2S at the property boundary should be less than 5
described in the World Bank Group            µg/m3
project documentation.
   The guidelines are expressed as
concentrations to facilitate monitoring.
Dilution of air emissions or effluents to
achieve these guidelines is
   All of the maximum levels should
be achieved for at least 95% of the time
that the plant or unit is operating, to be
calculated as a proportion of annual
operating hours.
Air Emissions

The following emissions levels should
be achieved:
449                                                                              Oil and Gas Development (Onshore)

                                                                Ambient Noise
Liquid Effluents                                                                 Maximum Allowable Leq
                                                                                    (hourly), in dB(A)
The emissions requirements given here
                                                                   Receptor        Daytime          Nighttime
can be consistently achieved by well-                                             07:00 - 22:00    22:00 - 07:00
designed, well-operated and well-
maintained pollution control systems.                           Residential;          55               45
  The following effluent levels should                          institutional;
be achieved:                                                    educational
                                                                Industrial;           70               70
Liquid Effluents from Onshore Oil                               commercial
and Gas Production
              Parameter                  Maximum value           The emission requirements given
                                        milligrams per liter   here can be consistently achieved by
                                              (mg/L)           well-designed, well-operated and well-
  pH                                           6-9             maintained pollution control systems.
  BOD5                                          50             Monitoring and Reporting
  Total suspended solids                        50
  (TSS)                                                        Frequent sampling may be required
                                                               during start-up and upset conditions.
  Oil and grease*                               20             Once a record of consistent
  Phenol                                         1             performance has been established,
                                                               sampling for the parameters listed
  Sulfide                                        1             above should be as detailed below.
  Total toxic metals**                           5
                                                                  Air emissions of above listed
                                                               parameters should be assessed on an
  Temperature increase                   less than 3°C1        annual basis. Liquid effluents from
                                                               production operations should be
      1 The effluent should result in a temperature increase   analyzed for the above listed
of no more than 3 degrees Celsius at the edge of the zone      parameters on a daily basis, except for
where initial mixing and dilution takes place. Where the       metals which can be monitored on a
zone is not defined, use 100 meters from the point of          monthly basis or when there are
discharge.                                                     significant process changes.
    * Up to 40 mg/L is acceptable for facilities producing        Monitoring data should be analyzed
less than 10,000 tpd.                                          and reviewed at regular intervals and
    ** Includes antimony, arsenic, beryllium, cadmium,         compared with the operating
chromium, copper, lead, mercury, nickel, selenium, silver,     standards so that any necessary
thallium, vanadium, and zinc.
                                                               corrective actions can be taken.
      Note: For direct discharge to surface waters.            Records of monitoring results should
                                                               be kept in an acceptable format. These
Ambient Noise                                                  should be reported to the responsible
                                                               authorities and relevant parties, as
Noise abatement measures should                                required, and provided to MIGA if
achieve either the following levels or a                       requested.
maximum increase in background
levels of 3 dB(A). Measurements are to
be taken at noise receptors located
outside the project property boundary.
450                                                          Oil and Gas Development (Onshore)

Key Issues                                   sources are provided for guidance and
                                             are not intended to be comprehensive):
The following box summarizes the key
production and control practices that        American Petroleum Institute (API).
will lead to compliance with emission        1989. API Environmental Guidance
requirements:                                Document: Onshore Solid Waste
                                             Management in Exploration and
• Maximize the use of freshwater gel-        Production Operations.
   based mud systems.
• Dispose drilling muds in a manner          Her Majesty's Inspectorate of Pollution
   which minimizes the impacts on            1992. United Kingdom. Chief Inspector's
   the environment. Reuse invert             Guidance to Inspectors. Environment
   (diesel-based) muds.                      Protection Act 1990. Process Guidance
                                             Note IPR 1/16: Petroleum Processes
• Reuse drilling mud pond decant             Onshore Oil Production.
•     Encourage the reuse of produced        Alberta Land Conservation and
      water for steam generation where       Reclamation Council. 1990. Literature
      steam is used to stimulate reservoir   Review on the Disposal of Drilling
      production.                            Waste Solids. Alberta Land
                                             Conservation and Reclamation
•     Minimize gas flaring.                  Research Technical Advisory
•     Scrub sour gases.                      Committee. Report No. 90-9.
                                             Edmonton, Alberta, Canada.
Further Information

The following are suggested as sources
of additional information (these

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