Geosteering

3. Field Location

4. Otter Field Summary 36.5 api Oil density 443 scf/bbl GOR 78.5 C Temp 1970m SS 92m Standoff 2062m SS Crest OWC Oct. 2002 subsea tie-back to Eider First Oil Approval 2001 Dev. Plan 2000 TotalFina 210/15a-6 Appraisal 1997 Fina 210/15a- DST 7650 BOPD Appraisal 1994 3D Seismic 1977 Philips 210/15-2 DST 4746 BOPD Discovery Brent Gp. Sandstones (98m thick N:G 90% Phi 24% Sw 32% Perm 400 mD Reservoir Easterly tilted fault block 4.3 km 2 Trap

5. Stratigraphy

6. Well T1

7. Otter Well T1

8. Geoteering Targets – Well T1 210 m 8 m T10 Sand 3000 m OWC N S

11. GeoVision Resistivity Logging PowerDrive VADN PowerPulse MWD 6 bps for real-time image GVR Gamma Ray Azimuthal Ring resistivity electrode for high resolution laterolog resistivity Button Resistivity electrodes for azimuthal images (deep, medium, shallow) PDC bit 3.5 m 21 m

12. GeoVision Resistivity Logging Recorded Mode Image 70 ft

13. GeoVision Resistivity Logging

14. Data Flow and Communication Operations Geology & Petrophysics (TFEE UK) Geosteering Specialist Schlumberger (War Room) Well Site Geologist INTERACT Real Time Data

15. T1 Trajectory and Areas of Uncertainty Top Brent Sub-seismic faults Throw on main fault Coal? N S

16. Forward Model N S

17. Staying in the Target Zone OUT OF TOLERANCE Target Zone 330 m of pay Ness plots as T20-T30 Caution

18. Landing the Well 9m low to prognosis Resistive Conductive

19. Landing the Well N S Dip = 4.7 deg Azimuth = 294

20. Landing the well Good quality T10 Poorer quality T10 Actual Prognosis Good quality T10 Poorer quality T10 T20 T30 T20 T30

21. Faults 2770m 2770 m

22. Tagging The Coal In the Ness RHOBB RHOBU Penetrating Coal From Top Below Coal Above Coal Below Coal Above Coal 2810m 2770m Fault

23. Sub-Horizontal to Coal

24. Top Ness Coal & Sub-Seismic Faults N S

25. Problematic (Shaley?) Section Encountered 2840 m 2812 m Ness T10 Fault 2854 m N S Increased GR Decrease RT Separation of ROBB and ROBU – close to bed boundary- thin bed

26. Tagged Heather? 2810m 2854m T20/T30 L Heather T10 Prognosis Actual

27. Based on Image Dips - Structural Cross-Section Indicates Silty T10 Unit not Heather. N S

28. Based on Image Dips - Structural Cross-Section Indicates Silty T10 Unit not Heather. N S

29. Main Fault BN/BS

30. Logging Response Into BS BN - Silty T10 BS Prognosis Into T10 Prognosis Into NESS

31. Dip as Expected – Maintain Pay Zone N S

32. Tagged Coal at TD (Top Ness Confirmed)

33. Pre-Drill N S

34. Post Drill Interpretation OWC 50 m Sand N/G: 95% (218 m) Pay N/G: 91% (210 m) Average Permeability: 1500 mD Average Porosity: 25% N S

36. Acknowledgements Logicom for 3D visualisation of RAB images Otter Partnership