Reservoir – Well Integrity Aspects of Carbon Capture and Storage

1. Reservoir – Well Integrity Aspects of Carbon Capture and Storage Mahmut Sengul Schlumberger Carbon Services Ankara December 5, 2006

2. Outline • Carbon Capture and Storage • Challenges • Monitoring • QRA • Examples • Way Forward

3. CCS Challenges • Enhancing oil recovery of existing fields • Pursuing development of marginal fields, • Commercialization of high CO2 content gas reservoirs • Continuing exploration in traditional acreages and unexplored areas, deep water

4. CO2 Storage Project Performance & Risk Assessment Field Dev. Plan Activities Verification Characterization Site Selection Monitoring Pre-Operation Operation Post-Storage 1.0 10 100 1000 Time (yrs.)

5. CO2 Leakage Path

6. CO2 - Rock interactions CO2 - Well interactions Diffusion Interfaces Hydraulic fracturing Escape through cement Fault crossing Corrosion Migration along fault Storage SEAL RES. 1 RES. 2 • • CO2 - Fluid interactions • • • • • • • • • • • Diagenetic front • • • • • • • • • • Hydrodynamism / Dispersion • • • • FAULT • Spill points CO2 Oil HC gas Aquifer Identification and Assessment of Leakage Pathways Modified after Total

7. Well Leakage • Casing • Corrosion • Cement • Micro-annulus • Cement alteration • Micro-cracks

8. Monitoring Tools Verification Monitoring – CO2 Displacement Verification Monitoring – Cap rock integrity Verification Monitoring – Well Integrity Environment Monitoring Operation Monitoring P,T, Volume, Rate X Seismic / VSP’s X X Microseismicity X X X EM Surveys X Cased-Hole Logging: CHFR,RST X Sampling X X Pressure tests X Sonic: MSIP X Ultrasonic: USIT/IBC X Corrosion X CO2-Sensors X X X X

9. Casing Corrosion • Image of inside or outside casing radius • 3D Viewer

10. Seal Elastomer Selection for Sour Services

11. Ensuring Long Term Wellbore Isolation through CO2-resistant Cement • Even oilfield cements performance tend to degrade with time leading to CO2 leakage Development of Novel Experimental Methods and Cementing Systems

12. Need for a CO2-Resistant Cement CO2 Interaction with Portland Cement • CO2 in presence of water results in a acidic environment • Carbonic acid • Chemical reactions in presence of Calcium • Carbonation • Dissolution • With • Variations of molar volume • Changes in Porosity, Permeability

13. Fresh water Standard Neat system Advanced cement system Shale Salt water or oil Carbonation rim: 0.2 mm Carbonation rim: 6 mm Zonal Isolation - Well & Completion IntegrityCO2 Resistant Cement 90°C-280 bars - One month - Supercritical CO2 Movie

14. 280 bar – 90 deg. C – 0.5 inch diameter, 2 inch long cores Neat vs New CO2-Resistant Cement Neat % One week One month New Cement

15. Carbonation/Dissolution Process Neat cement – 90 deg.C, 280 bars – 44 hours

16. Hydraulic Communication

17. Fresh water Shale Salt water or oil Well Integrity Assessment – Ultrasonic Measurements To Assess Cement Bonding and Detect Hydraulic Conductivity Cement / Formation Casing / Cement

18. Imaging Behind Casing – Tool Design

19. R2 R1 Cement Imaging Behind Casing - Flexural Mode

20. USIT Acoustic Impedance Increasing Contamination 8 6 4 2 0 Neat LiteCrete bond quality unclear Light Gas Liquid Cement Contaminated Cement Cement Water Gas Cement Evaluation Challenges

21. Air FWI Flexural Impedance Water Debonded LiteCrete LiteCrete Class G Tail cement Cement Water Gas Imaging Behind Casing Neat USIT Acoustic Impedance Light Gas Liquid Cement Contaminated Cement

22. Example: Channeled section in LiteCRETE cement Not identified by USIT and CBL!

23. Sonic Cement Evaluation Evaluation of cementing job quality, Using sonic measurements Casing mode attenuation is the function of cement bonding.

24. 5ft Receivers DCBL Using azimuthal data, MSIP DCBL is free of eccentralization effects up to 1/3” 3ft Receivers MSIP Cement Evaluation Improvement • MSIP BHC configuration enables discriminated CBL (DCBL) • Corrected for pipe and cement type • And independent of • Fluid effects, pressure, temperature • Tool normalization

25. August 2004: Crosswell Resistivity Baseline survey is acquired between the CO2 Injector well and the monitoring well 30m away. Both wells are cased. 30m EMI CO2 Storage in Frio Field, TX, USA Monitoring Well Injector Well • October 2004: 1600m3 CO2 are injected in the C-Sand layer. • December 2004: A second Resistivity survey is performed after CO2 injection is stopped. • Processing shows change in Resistivity between the 2 surveys due to CO2 migration • Further interpretation with integration of the petrophysical model built from borehole logs allows to characterize saturation changes due to the CO2 migration

26. Monitoring Using RST – S Measurement CO2 Injection : Start – Oct 4th / Stop - Oct 14th RST logging in the injection well (*) Sakurai et al. , SPWLA 46th – June 26-29th - 2005

27. Microseismics • Main applications: • Injection control • Avoid fracturing cap rock • Control CO2 displacement • Fault Re-activation

28. IW approx. 100 m OW 2 approx. 50 m OW 1 Microseismic: CO2 Injector and Monitoring Wells Planned

29. 1994 1999 2001 2002 Sleipner Seismic Monitoring Results “Leakage” into Sand wedge Courtesy SACS2

30. Conclusions • Reservoir integrity issues: • fault activation, caprock integrity,dissolution, precipitation • Wellbore Completion Integrity Issues in CCS: • Cement Integrity, Steel Corrosion • Completion Accessories • Technologies exist to address; • Integrity assessment and continuous monitoring • More high volume demonstration projects needed • Collaboration with all players is a must for success

31. Thank YouQuestions?

32. MEA CO2 Projects