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Learn about the advantages of using Cesium Formate Brine as a drill-in, completion, workover, and suspension fluid for HPHT gas wells. This non-toxic and non-hazardous fluid provides high density, thermal stability, compatibility with all reservoirs, and reduced environmental risks. Discover how it enables the construction of high-angle open hole screen completions in HPHT tight gas reservoirs, maximizing reservoir contact and production while offering improved economics and lower risk.
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SPE 145562 Life Without Barite: Ten Years of Drilling Deep HPHT Gas Wells With Cesium Formate Brine John Downs Cabot Specialty Fluids 2011 SPE/IADC Middle East Drilling Technology Conference, Muscat, 24-26 October
Cesium formate brine : Drill-in, completion, workover and suspension fluid for HPHT gas wells • Density up to 19.2 ppg/SG 2.3 • Drill-in and completion fluid • Non-toxic, non-hazardous – safe to handle • Little or no risk to the environment • Compatible with all reservoirs • Extends the thermal stability of polymers • Less corrosive than bromide brines • Stabilises shales • Inhibits hydrates 2011 SPE/IADC Middle East Drilling Technology Conference, Muscat, 24-26 October
Cesium formate brine produced by Cabot in Canada from pollucite ore Pollucite ore Cs0.7Na0.2Rb0.04Al0.9Si2.1O6·(H20) • Mined at Bernic Lake, Manitoba • Processed on site to Cs formatebrine • Cs formate brine production 8,000 bbl p.a. of 19.2 ppg • Brine stocks > 30,000 bbl @ 19.2 ppg • Brine supplied on leasing terms (i.e. per bbl per day) • Currently manage 30-40 jobs per year 2011 SPE/IADC Middle East Drilling Technology Conference, Muscat, 24-26 October
Leasing cesium formate brine Green and sustainable model – recognised by United Nations Conservation ( i.e. minimisation of cesium formate brine losses during transport, use and reclamation) is a key and essential feature of Cabot’s Chemical Leasing business model 2011 SPE/IADC Middle East Drilling Technology Conference, Muscat, 24-26 October
42deep HPHT gas fields developed using potassium and cesium formate brines, 1995-2011 2011 SPE/IADC Middle East Drilling Technology Conference, Muscat, 24-26 October
Conventional formate drilling fluid formulation -in field use since 1993 and good to 320oF Simple, effective, non-damaging reservoir drill-in fluid Used to drill entire wells, top to bottom, in sensitive environments (e.g. Barents Sea)
Cesium formate brine Where does it provide the highest value ? As a combined drill-in and completion fluid - enabling operators to construct high-angle open hole screen completions in HPHT tight gas reservoirs • Combined drilling and completion fluid (“one filtrate”) • Non-damaging to reservoir and screens • Cleans-up naturally during start-up (10-20 hours) • Low skins • No well stimulation required Perhaps the only fluid that can do this in an HPHT environment
Advantages of open hole screen completions in high-angle HPHT wells* Improved economics and lower risk • Maximise reservoir contact and production - Larger inflow areas in contact with reserves - Allow higher flow rates with lower flow resistance - Good results (low skins) with stand-alone screens • Lower cost - Quicker and easier to install, less NPT - 10% lower tangibles cost • More robust than cased holes - Less affected by formation compaction over time • Lower HSE risk than cased holes - No explosives , no live well work, fewer lifts, etc * From “HPHT Wells Best Practices Course” by Think Well Ltd 2011 SPE/IADC Middle East Drilling Technology Conference, Muscat, 24-26 October
Cesium formate brine used by BP and Statoil as combined HPHT drill-in and completion fluid in N. Sea 28 high-angle development* wells drilled and completed in 6 HPHT offshore gas fields • Huldra (6 ) • Devenick (1) • Kvitebjoern (8 O/B and 5 MPD) • Valemon (1) • Kristin (2) • Vega (5) * Except Devenick and Valemon (appraisal wells) Mostly open hole stand-alone sand screen completions Also Tune field : drilled with 13.3 ppg K formate brine , completed in K/Cs formate brine and suspended in K/Cs formate brine for 6-12 months 2011 SPE/IADC Middle East Drilling Technology Conference, Muscat, 24-26 October
Tune field – semi-HP/HT gas reservoir in the North Sea drilled and completed with formate brines 4 wells : 1,100-2,950 ft (350-900 m) horizontal reservoir sections. Suspended for 6-12 months in K/Cs formate brine after completion 2011 SPE/IADC Middle East Drilling Technology Conference, Muscat, 24-26 October
HPHT gas fields in northern North Sea drilled and completed with cesium formate brine Almost every field development (oil and gas) on this map has used formate brines as well construction fluids . Zinc bromide brine no longer used in Europe – too hazardous and damaging 2011 SPE/IADC Middle East Drilling Technology Conference, Muscat, 24-26 October
HPHT gas fields in the Norwegian Sea drilled and completed with cesium formate brine Formate brines also used as well construction fluids in Asgard, Draugen, Morvin and Njord fields 2011 SPE/IADC Middle East Drilling Technology Conference, Muscat, 24-26 October
Cesium formate brine first used as a combined drill-in and completion fluid in the Huldra field, 2001 • Offshore Norway • Gas condensate field • 6 wells • BHST: 297oF (147oC) • TVD : 12,795 ft (3,900 m) • Fluid density: 15.76- 16.34 ppg (SG1.89-1.96) • 754-1,125 ft (230-343 m) x 81/2” reservoir sections • Hole angle : 45-55o • 1–2 Darcy sandstone • Open hole completions, 6 5/8” wire wrapped screens 2011 SPE/IADC Middle East Drilling Technology Conference, Muscat, 24-26 October
Huldra – drill-in, logging and completion times (days) with cesium formate brine in well Drill, log and run lower completion in drilling fluid. Then displace to clean cesium formate brine and run upper completion. Finally displace to packer fluid 2011 SPE/IADC Middle East Drilling Technology Conference, Muscat, 24-26 October
Huldra – Fluid losses while drilling (cubic metres) 2011 SPE/IADC Middle East Drilling Technology Conference, Muscat, 24-26 October
Huldra – Production of recoverable gas and condensate reserves since 2001 (NPD data) • Plateau production from first 3 wells • - 10 MM m3 gas /day • - 30,000 bbl/day condensate • 80% of hydrocarbon reserves produced • by Year 6 2011 SPE/IADC Middle East Drilling Technology Conference, Muscat, 24-26 October
Gas production from Tune and Huldra fields drilled and completed with K/Cs formate brine 90% recovery of gas reserves (16-18 billion m3) produced in 7 to 8 years Source : Norwegian Petroleum Directorate- Fact Pages - November 2009 2011 SPE/IADC Middle East Drilling Technology Conference, Muscat, 24-26 October
Condensate production from Tune and Huldra fields drilled and completed with K/Cs formate brine 90% recovery of condensate reserves (3-5 million m3) produced in 5 to 7 years Source : Norwegian Petroleum Directorate- Fact Pages - November 2009 2011 SPE/IADC Middle East Drilling Technology Conference, Muscat, 24-26 October
Seven years of cesium formate brine use as combined drill-in and completion fluid in Kvitebjoern field, 2004 -present • Offshore Norway, 190 m water depth • Gas condensate field, 775 bar • 13 wells to date – 8 O/B, 5 in MPD • BHST: 311oF (155oC) • TVD : 13,120 ft (4,000 m) • Fluid density: 16.8 ppg (SG 2.02) for O/B • 914 -1,910 ft (279-583 m) x 81/2” reservoir sections • Hole angle : 20-40o • 100 mD sandstone, long interbedded shale and coal sequences • 6 wells completed in open hole : 300-micron single wire-wrapped • screens. Remainder cased 2011 SPE/IADC Middle East Drilling Technology Conference, Muscat, 24-26 October
A few of the highlights from Kvitebjoern Operator comments after well testing (Q3 2004 ) “The target well PI was 51,000 Sm3/day/bar This target would have had a skin of 7” “A skin of 0 would have given a PI of 100,000” “THE WELL A-04 GAVE A PI OF 90,000 Sm3/day/bar (ANOTHER FANTASTIC PI)” The Well PI was almost double the target Fastest HPHT well completion in the North Sea 2011 SPE/IADC Middle East Drilling Technology Conference, Muscat, 24-26 October
Economic benefits from the use of cesium formate brine in HPHT gas field developments Improved HPHT well control and safety • No well control incidents in 28 HPHT drilling and completion ops over 10 years (maybe 800 days in HPHT high-angle open hole ?) • Factors contributing to improved well security and safety: - Elimination of barite and its sagging problems - Elimination of oil and its gas solubility problem - Low solids brine Low ECD* and swab pressures - Inhibition of hydrates - Ready/rapid surface detection of well influx - No hazardous zinc bromide ! * ECD in Huldra, Kvitebjoern and Kristin wells : 0.33-0.50 ppg (SG 0.04-0.06) 2011 SPE/IADC Middle East Drilling Technology Conference, Muscat, 24-26 October
Economic benefits from the use of cesium formate brine in HPHT gas field developments Improved well performance and recovery of reserves • “High production rates with low skin” * • “ We selected cesium formate to minimise well control problems and maximise well productivity”* * Quotes by Statoil relating to Kvitebjoern wells (SPE 105733) 2011 SPE/IADC Middle East Drilling Technology Conference, Muscat, 24-26 October
Economic benefits from use of cesium formate brine in HPHT gas field developments • Faster completions • - Drill-in and completing with cesium • formate allows open hole completion • with screens • - Clean well bores mean no tool/seal • failures or blocked screens • - Completion time 50% lower than wells • drilled with OBM • Time saved per well: 25 days • Quote by operator:“ fastest HPHT completion operation ever performed in North Sea (12.7 days)” 2011 SPE/IADC Middle East Drilling Technology Conference, Muscat, 24-26 October
Economic benefits from use of cesium formate brine in deep gas field developments • Operational efficienciesLower NPTLower costs • No differential sticking • No well bore instability* • Pipe and casing running speeds are fast • Mud conditioning and flow-check times are short • Displacements simplified, sometimes eliminated • Formate drilling fluid = formate completion fluid • * Quote by operator : “ No washouts were experienced in any of the wells during drilling through long sections of • interbedded shales in the Kvitebjoern reservoir (50/50 shale and sand ) with cesium/potassium formate fluid” Flow check fingerprint for a Huldra well 2011 SPE/IADC Middle East Drilling Technology Conference, Muscat, 24-26 October
Economic benefits from the use of cesium formate brine in HPHT gas field developments Good reservoir definition • High density filtrate and no barite • Filtrate Pe up to 259 barns/electron • Unique Cs feature - makes filtrate invasion • highly visible against formation Pe of 2-3 b/e • Ideal for defining permeable sands • Consistent and reliable net reservoir definition • from LWD “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.” (SPE 105733) 2011 SPE/IADC Middle East Drilling Technology Conference, Muscat, 24-26 October
Economic benefits from the use of cesium formate brine in HPHT gas field developments Good reservoir definition • Highly conductive fluid • Clear resistivity images • Information provided: • - structural dip • - depositional environment • - geological correlations 2011 SPE/IADC Middle East Drilling Technology Conference, Muscat, 24-26 October
Summary 10 years of field use has demonstrated that cesium formate brine can improve the economics of HPHT gas field developments by: • Enabling long high-angle well constructions completed in open hole with screens • Making the well construction process faster and easier • Improving well/operational safety and reducing risk • Delivering unimpaired wells with high production rates • Enhancing reservoir definition 2011 SPE/IADC Middle East Drilling Technology Conference, Muscat, 24-26 October