This document summarizes the geosteering objectives, issues, and results for Well T1 drilled in the Otter Field. The key objectives were to maintain standoff from the oil water contact, target the best quality "T10 sands", avoid poor quality sandstones and coals. Real-time resistivity imaging allowed adjustments to the well trajectory and confirmation of targets like coals. The well landed within tolerance and identified key geological features like faults. Real-time data helped optimize the well path for maximum reservoir contact.

2. Introduction Introduction to Otter Drilling Targets & Requirements GeoVision Images and Geosteering Data-flow and Communication in the decision process Case Study Otter 210/15a-T1 Conclusions

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

9. Geosteering Objectives Maintain Standoff from OWC Target Best Quality Rock (T10 sands) 8m target (upper part 4 m target) Avoid poor quality sandstones above T10 Avoid Coals in Top Ness immediately below T10 Reinterpret structure real time and adjust trajectory to account for sub-seismic faults

10. Geosteering Issues Lag time Time between receiving data and making the decision (analysis time) Time between making the decision and achieving the target objective (trajectory adjustment time) 4 deg per 30m, if you want to change the trajectory by 6 deg then 45 m is required Distance between the bit and the measurement device Things can change during the lag time Be prepared for the unexpected No real ‘look ahead’. You can look up and look down but not ahead

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

35. Conclusions – Real Time Images Real time images and log data allow rapid adjustment of the structural model The well trajectory can be continually adjusted to maximise pay 4 deg per 30 m Side tracks can be avoided Reduced rig time Reduced well time Value added data for structural review and reservoir interpretation

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