Reducing Greenhouse Gas Emissions Geological Storage of CO2 by uji43842

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									Design of CO2 storage in aquifers
and oil reservoirs



 Tara C LaForce, Imperial College Department of Earth Science and Engineering

 Quorum Oil & Gas Technology Fund Technical Symposium, Sept 18, 2008
Background
        Carbon Capture and Storage (CCS)




   736 Gt in North Sea alone (DTI) ≈
   CO2 produced by all UK population for 100 years!!!
  Sleipner Project
 1 million tonnes CO2 injected per year
 CO2 separated from produced gas
 Avoids Norwegian CO2 tax
 Gravity segregation and flow under shale layers controls
CO2 movement
Aquifer storage




             http://www.netl.doe.gov/technologies/carbon_seq/refshelf/atlas/index.html
How could CO2 escape?
       Abandoned Well       CO2 Injection
                                Well



               5            4
         6              3
                                    1       2
Spread of CO2 is an inherently multi-scale process




                                         170m
                                                        2280m
                                          3200m




   Pore scale:       Laboratory scale:              Field scale:
Model flow through    Model flow using            Model flow using
  pores directly        continuum                    continuum
    mm-mm              approximation               approximation
                           cm-m                        m-km
 CO2 trapping

 As CO2 migrates through the rocks, it is trapped
 in pore-scale bubbles that can not move further
                                         CO2
Rock
                                         bubbles




Water


                                            Dong, 2007
Design of CO2 storage

A case study on a highly                               Producer
heterogeneous field:

 Use chase water to trap             Injector
CO2 during injection

 1D results are used to
design a stable displacement

 Simulations are used to
optimize trapping
                               SPE 10 reservoir model, 1,200,000 grid cells
                               (60X220X85), 7.8 Mt CO2 injected.

                                                    Qi et al., SPE 109905
               ID results for aquifer storage
                                                                                   Dissolution                           Advancing
      1
                                                                                                    Chase                CO2 front
                                                                                   front
                                                                                                    brine front
     0.9
                                                                         0.3
     0.8

     0.7

     0.6
                                                                         0.2
     0.5
fg




                                                                                   Trapped


                                                                    Sg
     0.4                                            fg
                                                   Series1
                                                                                   CO2             Mobile CO2
     0.3                                            f gi = 0.85
                                                   fgi=0.85              0.1
                                                    Sgi = 0.295
                                                   Sgi=0.26
     0.2
                                                    f gi = 0.5
                                                   fgi=0.5
     0.1
                                                    Sgi = 0.190
                                                   Sgi=0.19
      0                                                                   0
           0   0.1   0.2   0.3   0.4   0.5   0.6      0.7     0.8
                                                                               0             400         800      1200
                                 Sg
                                                                                                   Distance (m)
                                                                                                                         Simulation
           The CO2-phase fractional flow fg as a                                                                         Analytical
           function of CO2 (gas) saturation, Sg.                                                                         solution


                                                                                                       Qi et al., SPE 109905
 3D results for aquifer storage

 20 years of water and CO2 injection followed by 2 years
 of water injection in realistic geology




                                170m
170m




         Z                             Z




                       Y                            Y
               X                           X
       3200m         2280m         3200m            2280m


       Trapped CO2 saturation          Mobile CO2 saturation

 95% of CO2 trapped after 4 years of water injection
                                                     Qi et al., SPE 109905
       How long until the CO2 is immobilized?

        Depends on wettability of rock and trapping model




 Lets measure this
 directly…
Qi et al., to appear JGGC
CO2 trapping experiments




                                         Flow path of oil
Sand-packed column injected with non-
wetting fluid (oil dyed red).
                                        Pentland et al., SPE 115697
Trapping as a function of initial saturation
       0.16

       0.14

       0.12

       0.10
 Sor




       0.08

       0.06
                                 vertical fingering - 30 mL
       0.04                      vertical fingering - 50ml
                                 vertical fingering - 80 mL
       0.02                      horizontal flooding - GC

       0.00
          0.00   0.20   0.40      0.60               0.80

                           Soi
                                           Pentland et al., SPE 115697
Comparison: trapping equations & data

      0.14


      0.12


      0.10


      0.08                                                         Vertical Fingering
Sor




                                                                   Land Equation

      0.06                                                         Aissaoui Equation

                                                                   Jerauld Equation

      0.04                                                         Kleppe Equation

                                                                   Spiteri Equation

      0.02                                                         Ma Equation

                                                                   Agarwal Equation 1

      0.00
         0.00   0.10   0.20   0.30   0.40         0.50   0.60    0.70         0.80      0.90
                                            Soi


                                                                Pentland et al., SPE 115697
General injection strategy

To maximize CO2 storage in an aquifer:

 Inject CO2+brine where mobility ratio = 1.0 for a
stable displacement
 Inject chase brine that is 25% of the CO2 mass
  90-95% of the CO2 is trapped for most realistic case
   As little as 65% may be trapped for worst case
  It all rests on how much is trapped as a function of initial
   saturation…




                                                  Qi et al., to appear JGGC
Storage in oil and gas reservoirs




             http://www.netl.doe.gov/technologies/carbon_seq/refshelf/atlas/index.html
How could the CO2 escape?
Presence of hydrocarbons indicate that the geologic
seal is good
           Abandoned Well              CO2 Injection
                                            Well



                   5                  4
           6               3?
                                              1        2
   Storage in oil and gas reservoirs
    Practical experience injecting CO2 into oil reservoirs
    Knowledge of geology so less chance of CO2 escaping
    Far from emission sources

    As CO2 migrates it is trapped at the pore scale
    CO2 will mix with oil and improve oil recovery

                        CO2 separator and              Production Well
Injection Well
                           compressor



        CO2                                            Oil
                     Oil/CO2 mixture
                                                  Water
   CO2 storage and EOR

 CO2 injection displaces oil    Competing goals: CO2 storage vs.
very efficiency                  EOR in WAG injection
…but has poor sweep




Water alternating with gas
(WAG) injection improves sweep
     ID results for reservoir storage
                0.52
                               Mobile CO 2
                               front                                         Advancing oil
                 0.5   Chase                                                 front
                       water
                       front
                0.48
         S_HC




                0.46
                                             Mobile Oil
                                                                       Simulation
                0.44                                                   Analytical

                                                                       Trapped CO2
                0.42
                                                                       Mobile CO2

                 0.4
                       0         2000           4000            6000   8000                  10000
                                                     Distance (m)

First-contact miscible CO2 injection
CO2 injection at fCO2=0.7 followed by chase water injection

                                                                               Qi et al., SPE 115663
       Storing CO2 in the oil field
   Trapped CO2
                                    Increased oil recovery offsets
                                    cost of capture, making CO2
                                    storage more economic
52 m
                                    Currently there are 66 CO2
                                    injection projects worldwide
                          366 m




                                    Cumulative Production (m3)
 670 m
                                                                 8E+05       Oil production
       Mobile CO2                                                6E+05

                                                                 4E+05
52 m
                                                                 2E+05              CO2 production

                                                                 0.0
                        366 m                                            0    100   200       300   400   500   600
 670 m                                                                              Time (days)
          CO2 volumetric fraction

                                                                                      Qi et al., SPE 115663
Conclusions

 Trapping is an important mechanism to store CO2 as an
immobile phase. Our study showed that brine + CO2 injection can
trap more than 90% of the CO2 injected
 We have proposed a design strategy for CO2 storage in
aquifers, in which CO2 and formation brine are injected
simultaneously followed by chase brine.
Results are very sensitive to trapping model
Field-scale simulation combined with pore-scale network
modelling can capture both the large-scale heterogeneity of the
reservoir and the pore-scale effects of trapping
Current and future work

Injection strategy design

   Continue gathering experimental data, since the
    trapping model used has a significant impact on the
    results
   Include additional physics, such as salt precipitation
    –simulator has been developed
Thanks To:
All of you for listening!



Research Sponsors:

    Grantham Institute for Climate Change
    Shell Grand Challenge on Clean Fossil Fuels
    UK Engineering and Physical Sciences Research
    Council
The CO2 team

Martin Blunt – Professor of Petroleum Engineering
Tara LaForce – Lecturer in Petroleum Engineering
Stefan Iglauer – Post-doc, runs the experimental programme
Ran Qi – 3rd year PhD student. Field-scale simulation.
Saleh Al-Mansoori – 2nd year PhD student. Experiments of trapping.
Christopher Pentland – 1st year PhD student. Experiments and pore-
scale modelling.
Erica Thompson – 1st year PhD student. Analytical solutions to the
transport equations.
Aaron Goater and Lorena Lazaro – PhD students starting in October
2008

								
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