Integrated Evaluation of CO2 Sequestration: Use of Core, Wireline Logs, and Seismic Data

1. Integrated Evaluation of CO2 Sequestration: Use of Core, Wireline Logs, and Seismic Data Shinichi Sakurai, Bureau of Economic Geology, Sean Gulick Institute for Geophysics Susan Hovorka, Bureau of Economic Geology, Jackson School of Geosciences, The University of Texas at Austin International Workshop on Core-Log-Seismic Integration

2. Background • Tohoku University • Core Laboratories, Inc. • BP • ARCO • BEG

3. Outline • Core and Log Integration • CO2 Project • Gulf of Mexico • Log and Seismic Tie • Log Edit, Fluid Substitution, Time Match • Changes in Sonic and Crosswell Data

4. Frio Brine Pilot Offshore Texas Mars Field Location of Fields

5. Frio Brine Pilot • South Liberty field • Discovered in 1925 • Oil from Yegua sand (9,000 ft) • Injection of CO2 into Frio Sandstone (5,000 ft)

6. Cores Cut and Objectives Anahuac Shale C Sand Seal-Rock Property Reservoir Quality K & Φ for Model Input Used CO2 to preserve friable cores

7. Core Samples Scanned Image w/in Alum Sleeve Thin Section Photo of Sand

8. 10000 1000 100 Permeability (md) 10 1 0.1 0 10 20 30 40 Porosity (%) Core Analysis Results Hydrologic test ~ 2,400 md Conventional analysis made @ 1,800 psi • Updated input of simulation model • Higher Φ & K • New perforation

9. Open-Hole Log Analysis with Core Data Very high reservoir quality Φ 30+ % K ~2,000 md Lithology agreed well with XRD

10. FMI Images GR Hole Dir Dip Structure Dip 18 Degree South C sand Formation Micro Imager Borehole Image of Conductivity No Faults Observed 0 10 20 30 90

11. Outline • Core and Log Integration • CO2 Project • Gulf of Mexico • Log and Seismic Tie • Log Edit, Fluid Substitution, Time Match • Changes in Sonic and Crosswell Data

12. Fluid Substitution • Can we see difference between high gas saturated sand and low gas saturated (~10%) sand • Acoustic velocity slows down even with 5~10% gas in pore space • Density change is larger • Example from Offshore Louisiana

13. Fluid Substitution Offshore Texas Well Sw = 0.2 Producing Gas Sand Low density & Slow Sonic

14. Fluid Substitution Offshore Texas Well Sw = 0.2 Producing Gas Sand Sw = 0.9 Low Gas Sand Change between 2 cases is small It is not easy to distinguish from commercial gas sand & low gas sand

15. Tie with 3D Seismic Data • Made synthetics for Offshore Texas well • Aided to match time & depth

16. Tie with 3D Seismic Data • Offshore Texas well • Mismatch of amplitudes • Made time changes

17. Tie with 3D Seismic Data • Offshore Texas well Density log is noisy over washed-out interval Need to fix and remove app. Amplitude

18. Tie with 3D seismic data • Offshore Texas well • Can see thin sands at • 13,000 • 13,500 • 15,000

19. Sonic Transit Time Before and After Injection Postinjection cased-hole log 2.03 km/s OH Dtco overlay Baseline open-hole log 3.05 km/s C sand perf.

20. Injection Well Distance (ft) Monitor Well ‘B’ Sand G.L. Depth (ft) Top of ‘C’ Sand CO2 Plume Change of Velocity Before and After Injection Tom Daley (LBNL)

21. CONCLUSIONS • We worked Wireline Log data with Core data and Geophysical data • Understanding Geology is a key for Integrated Interpretation

22. Thank You