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Economics of constructing deep HPHT gas wells with formate brines

Economics of constructing deep HPHT gas wells with formate brines

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  • 90% recovery of recoverable condensate reserves in 4 years ! Think of leasing cesium formate brine as an investment in the future profitability of your gas condensate field development.
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Spe 130376 Slides Presentation Transcript

  • 1. SPE 130376 A Review of the Impact of the Use of Formate Brines on the Economics of Deep Gas Field Development Projects
    John Downs
    Cabot Specialty Fluids
    2010 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 January
    Gas 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 WCF
    High 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 January
    Super 13Cr, 1 month
    22Cr, 2 months
    25Cr, 2 months
  • 14. Extreme conditions in deep wells expose the performance deficiencies of conventional WCF
    High pressures and hard rocks
    High 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 January
    Best 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 January
    FGE -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 January
    Prices the full operational costs, waste costs and the cost of “incidents”
  • 21. Cost of fluid ownership
    2010 SPE Deep Gas Conference, Bahrain, 24-26 January
    BrineWise 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
    • 32. Degrading well integrity/durability
    • 33. Raising waste management costs and liabilities – i.e. high cost of
    ownership
    ...And if they are damaging to the formation they may
    reduce the rate of revenue generation
    2010 SPE Deep Gas Conference, Bahrain, 24-26 January
  • 34. How do you make a WCF that performs better under extreme conditions in deep gas wells ?
    Remove the source of the problems
    • Remove the solid-weighting agents
    • 35. Remove any halide salts (chlorides and bromides)
    • 36. Preferably remove any hydrocarbons too (well control risk and logging issues)
    Formate brines developed by Shell Research, 1985-95
    2010 SPE Deep Gas Conference, Bahrain, 24-26 January
    Density to SG 2.3 /19.2 ppg/143 pcf
    No solids
    No halides
    No hydrocarbons
    Anti-oxidant
    Drilling, completion, workover and suspension fluids for deep gas wells
  • 37. 2010 SPE Deep Gas Conference, Bahrain, 24-26 January
    1995 – Formate brines used for first time by Mobil to drill and work over deep gas wells, onshore, northern Germany
    Walsrode field – onshore, high-angle slim hole wells Z1, Z5, Z6 and Z7
    TVD : 4,450-5,547 metres
    Reservoir: Sandstone 0.1-125 mD
    BHST : 315oF (157o C)
    Section length: 345-650 metres
  • 38. Outcome of Mobil’s first drilling trials with formate brines in onshore deep gas wells - 1995/96
    Absence of weighting solids has a clear impact on efficiency and
    economics 1,2
    “Use of formate drilling fluid ….eliminated most of the previous hole problems
    ...resulted in a dramatic increase in drilling performance and hydraulics…
    and significantly reduced well costs”
    Low-solids drilling fluid concept appears to be validated
    1)Sundermann, R. and Bungert, D.: “Potassium-Formate-Based Fluid Solves High Temperature Drill-In
    Problem,” Journal of Petroleum Technology (November 1996) 1042
    2) Bungert, D., Maikranz, S., Sundermann, R., Downs, J., Benton, W. and Dick, M.A.: “The Evolution and
    Application of Formate Brines in High-Temperature/High-Pressure Operations”, IADC/SPE 59191, IADC/SPE
    Drilling Conference, New Orleans, 23-25 February 2000.
    2010 SPE Deep Gas Conference, Bahrain, 24-26 January
  • 39. Formate brines used by Mobil in 15 deep gas well constructions in northern Germany 1995-1999 (SPE 59191)
    2010 SPE Deep Gas Conference, Bahrain, 24-26 January
  • 40. Huldra field, HP/HT gas condensate
    • BHST: 297oF
    • 41. TVD : 3,900 metres/12,795 ft
    - Fluid density: 15.75 ppg/118 pcf
    - 6 wells – 600 ft reservoir sections 5-7/8” at 45-55o
    - 1–2,000 mD sandstone
    • Open hole, wire wrapped screens
    Justification for using formate
    - Improve well control !
    - Lower ECD
    - Run completion in same fluid
    - Low risk of screen plugging
    - Shale stabilisation
    - Lubricating
    - Safe for crews
    - Environmentally benign
    2010 SPE Deep Gas Conference, Bahrain, 24-26 January
    2001 - Formate brines used for first time by Statoil to drill and complete 6 deep HPHT gas wells, offshore, Norway
    Operator had experienced kicks when using barite-weighted fluids
  • 42. Outcome of Statoil’s first drilling trials with formate brines in offshore deep gas wells - 2001/02
    Efficiencies and economies provided by drilling at depth with low-
    solids brine 1
    “Stable hole, low ECD, good hole cleaning and stable fluid has led to rig time savings due to:
    • Fast tripping speed
    • 43. Fast casing running speeds
    • 44. Less mud conditioning and wiper trips than with conventional drilling fluids”
    Low-solids fluid enables faster well constructions at depth
    1) Saasen, A., Jordal, O.H., Burkhead, D., Berg, P.C., Løklingholm, G., Pedersen, E.S., Turner, J. and Harris, M.J.:
    “Drilling HT/HP Wells Using a Cesium Formate Based Drilling Fluid,” IADC/SPE 74541, IADC/SPE Drilling
    Conference, Dallas, 26-28 February 2002.
    2010 SPE Deep Gas Conference, Bahrain, 24-26 January
  • 45. Deep and/or HPHT gas fields developed using formate brines as WCF 1995-2009
    Author has good information on 35 fields
    2010 SPE Deep Gas Conference, Bahrain, 24-26 January
  • 46. Formate brine used in > 140* deep and/or HPHT gas wells , 1995- present
    Drilling, completion, workover, suspension and packer fluids
    At densities up to SG 2.25 (18.7 ppg or 140.2 pcf)
    At BHST up to 235oC (450oF)
    For periods of > 10 years dowhole (packer fluid applications)
    In sandstone and carbonate reservoirs, 0.01 mD up to 4 Darcy
    Wide variety of completions – barefoot open hole, cased and
    perforated, with sand screens and gravel packs
    * Actual field/well numbers will be greater – but some are not documented
    2010 SPE Deep Gas Conference, Bahrain, 24-26 January
  • 47. Deep gas fields where formate brines have been used as WCF – segmented by operator
    2010 SPE Deep Gas Conference, Bahrain, 24-26 January
  • 48. Formate brines used in the world’s largest HPHT gas field development – Elgin/Franklin
    2010 SPE Deep Gas Conference, Bahrain, 24-26 January
    Also the deepest HPHT gas field in North Sea
    Cesium formate brine used by TOTAL in 34 well construction operations in 8 deep gas fields in period 1999-2009
    B
  • 49. Gaining an economic perspective – Scope of review
    Collect and analyse user observations on operational well
    construction efficiencies
    2) Look for examples of long-term production rates, for evidence
    of production efficiencies
    Only examined Cs formate brine applications (more extreme conditions)
    128 user observations extracted from 5 published field case histories
    8-year production figures found for two HPHT gas fields drilled and
    completed entirely with potassium/cesium formate brines
    Observations on well construction efficiencies tend to be qualitative
    rather than quantitative
    2010 SPE Deep Gas Conference, Bahrain, 24-26 January
  • 50. Economic benefits from use of formate brines in deep gas field developments – Results of review
    Operational efficiencies provide well construction cost reductions
    Better drilling environment gives rig-time savings
    - Stable hole: see LWD vs. WL calipers in shale
    - Elimination of well control and stuck pipe incidents
    - Good hydraulics, low ECD
    - Good ROP in hard abrasive rocks
    “ a remarkable record of zero well control incidents in all 15
    HPHT drilling operations and 20 HPHT completion operations”
    2010 SPE Deep Gas Conference, Bahrain, 24-26 January
  • 51. Economic benefits from use of formate brines in deep gas field developments – Results of review
    Operational efficiencies provide well construction cost reductions
    2. Allowing faster and easier movements of tubulars and fluids
    - Pipe and casing running speeds are faster
    - Mud conditioning and flow-check times shorter
    - Displacements simplified, and sometimes eliminated
    (i.e. formate drilling fluid = formate completion fluid)
    Quote by operator : “ Improved well economics by increasing trip speed”
    2010 SPE Deep Gas Conference, Bahrain, 24-26 January
  • 52. Economic benefits from use of formate brines in deep gas field developments – Results of review
    Operational efficiencies provide well construction cost reductions
    3. Faster completions
    HPHT gas well completion times
    from the Rushmore database
    • Wells drilled with OBM vs
    cesium formate brine
    Quote by operator : “ fastest HPHT completion operation ever performed in North Sea (12.7 days)”
    2010 SPE Deep Gas Conference, Bahrain, 24-26 January
  • 53. Efficient delivery of gas reserves (revenues)
    Tune and Huldra fields – drilled and completed with formate brines
    90% recovery of reserves (16-18 billion m3) produced in 7 to 8 years
    2010 SPE Deep Gas Conference, Bahrain, 24-26 January
    Source : Norwegian Petroleum Directorate- Fact Pages - November 2009
  • 54. Efficient delivery of condensate reserves (revenues)
    Tune and Huldra fields – drilled and completed with formate brines
    90% recovery of reserves (3-5 million m3) produced in 4 to 6 years
    2010 SPE Deep Gas Conference, Bahrain, 24-26 January
    Source : Norwegian Petroleum Directorate- Fact Pages - November 2009
  • 55. Conclusion
    Results of thisreview suggests that the use of formate brines in
    deep gas field developments has reduced well construction times
    and costs by :
    • Providing a better drilling environment
    • 56. Allowing faster/easier movements of WCFand hardware
    • 57. Allowing faster completions
    The non-damaging nature of formate brines may have contributed to
    the efficient production of recoverable hydrocarbon reserves from
    two HPHT gas/condensate fields examined in this study.
    2010 SPE Deep Gas Conference, Bahrain, 24-26 January
  • 58. Footnote 1
    Results of independent Eco-efficiency study by BASF show that
    cesium formate brine is the most sustainable high-density completion
    fluid
    2010 SPE Deep Gas Conference, Bahrain, 24-26 January
    Leasing of cesium formate brine encourages a sustainable approach
  • 59. Footnote 2
    2010 SPE Deep Gas Conference, Bahrain, 24-26 January
    Good reservoir definition in cesium formate brine
    “Using photoelectric factor and bulk density data, combined with resistivity measurements from both the LWD drill pass and the ream pass, produces a very reliable and consistent net reservoir definition.”
  • 60. Footnote 3
    2010 SPE Deep Gas Conference, Bahrain, 24-26 January
    Good reservoir definition in cesium formate brine
    “Applying a conductive drilling fluid in all production wells drilled in a field also provides the possibility of running high quality resistivity image logs (FMI). Extensive use of such logs provides the geo-modelers with detailed information regarding structural dip, depositional environment, sedimentary features, facies, and geological correlations.”