This document summarizes a presentation on the use of formate brines for deep gas field development projects. It finds that formate brines provide operational efficiencies over conventional drilling fluids by providing a more stable wellbore, faster tripping speeds, and fewer well control incidents. These efficiencies can reduce well construction costs and times. The document also finds that fields developed using only formate brines were able to recover 90% of reserves within 7-8 years, indicating formate brines may enable more efficient production.

1. SPE 130376 A Review of the Impact of the Use of Formate Brines on the Economics of Deep Gas Field Development Projects John DownsCabot Specialty Fluids2010 SPE Deep Gas Conference, Bahrain, 24-26 January

2. Deep gas wells are expensive ..... 12 times more expensive than conventional gas wells * Last 10% of deep gas well accounts for 50% of total well cost *2010 SPE Deep Gas Conference, Bahrain, 24-26 JanuaryGas well cost versus depth*** US Department of Energy website - Onshore gas well costs in USA** Snead (2005) - The Economics of Deep Drilling in Oklahoma

3. Some basic principles for improving the economics of deep gas field developments ? Working at depth is expensive, so.. : Use technologies that will accelerate deep well construction * Get it right first time – avoid costly interventions Know what is down there - ensure accurate reservoir evaluation Focus on recovering your substantial investment - extract recoverable reserves as fast as the reservoir (engineers) will allow * US DOE ”Deep Trek” R&D programme aimed at identifying some of these technologies 2010 SPE Deep Gas Conference, Bahrain, 24-26 January

4. How can well construction fluids influence economics of deep gas field developments ? WCF performance impacts on costsandrevenues Time taken to drill and complete the required wells

5. Well design and placement

6. Well control and safety

7. Well integrity, lifetime and maintenance

8. Logging capability and interpretation

9. Waste management and liabilities

10. Rate of recovery of reserves 2010 SPE Deep Gas Conference, Bahrain, 24-26 January

11. Extreme conditions in deep wells expose the performance deficiencies of conventional WCFHigh temperatures and hydrothermal chemistry Barite sag, leading to well control problems

12. Need gels, causing high swab, surge and start-up pressures

13. Corrosive gas influx into halide brines will destroy ”corrosion resistant alloys” 2010 SPE Deep Gas Conference, Bahrain, 24-26 JanuarySuper 13Cr, 1 month22Cr, 2 months25Cr, 2 months

14. Extreme conditions in deep wells expose the performance deficiencies of conventional WCF High pressures and hard rocksHigh solids loading have negative effects on ECD, ROP, bit life, swab and surge, differential sticking, hole cleaning, tools, screens, seals, formation, etc ......! 2010 SPE Deep Gas Conference, Bahrain, 24-26 JanuaryBest fluid for high ROP and long bit-life is solids-free water … From :SPE 112731 “Optimisation of Deep Drilling Performance with Improvements in Drill Bit and Drilling Fluid Design”

15. Extreme conditions in deep gas wells expose the performance deficiencies of conventional WCF Narrow drilling windows, aggravated by pressure depletion from production Production while drilling lowers pore pressure and fracture gradient

16. Solids-weighted muds may not be able to stay within ECD limits

17. Well control problems if fracture pressure gradient exceeded

18. Increasingly the domain of MPD and ”designer fluids” providing Fracture Gradient Enhancement (FGE) or Stress Caging effects 2010 SPE Deep Gas Conference, Bahrain, 24-26 JanuaryFGE -Increasing hoop stresses around the well bore by creating short stabilised fractures

19. Conventional high-density completion fluids used in deep gas wells have a high cost of ownership 2010 SPE Deep Gas Conference, Bahrain, 24-26 January

20. Software tool now available that calculates the full cost of owning and using high-density completion fluids 2010 SPE Deep Gas Conference, Bahrain, 24-26 JanuaryPrices the full operational costs, waste costs and the cost of “incidents”

21. Cost of fluid ownership 2010 SPE Deep Gas Conference, Bahrain, 24-26 JanuaryBrineWise tool calculates all fluid ownership costs Purchase /leasing fee

22. Transport onshore /offshore

23. Sub-optimal rig time

24. Well clean up time

25. Waste treatment and disposal

26. Stand-by time

27. Isolation and treatment of produced water Production delays

28. Production handover delays

29. Liabilities and legal fees arising from splashes, spills, releases Factors in damage caused to company reputation by incidents

30. So.. do conventional WCF influence the economics of deep gas field developments ? Undoubtedly YES – conventional WCF have problems and influence economics by increasing overall development costs of deep gas fields Lengthening the time taken to drill and complete

31. Creating well control and safety risks