Drilling Fluids in an HP/HT Reservoir: Experiences With Three Different Systems on the Kristin Field Development

Hansen, Svein; Breivik, Dag Helge; Gjonnes, Morten; Svanes, Kåre; Vujovic, Mijo; Svela, Per Einar; Sorheim, O. I.

doi:10.2118/103336-ms

“…With a riser margin of SG 0.09 giving a drilling window of only SG 0.09 it was critical that a low ECD drilling fluid was used in the reservoir section [Hansen et al, 2006]. With a riser margin of SG 0.09 giving a drilling window of only SG 0.09 it was critical that a low ECD drilling fluid was used in the reservoir section [Hansen et al, 2006].…”

Section: Kristinmentioning

confidence: 99%

Life Without Barite: Ten Years of Drilling Deep HPHT Gas Wells With Cesium Formate Brine

Downs

¹

2011

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The tradition of using barite to increase the weight of drilling fluids dates back to the early-1920's and, while it has been of great benefit to the oil industry over the past 90 years, it has also caused some chronic and persistent well construction problems along the way. These problems, which are very familiar to drillers, include well control difficulties, stuck pipe incidents and formation damage.The oil industry has known since the 1970's that replacing barite with suitable non-damaging solutes in reservoir drill-in fluids is an effective way of reducing formation damage, simplifying operations and eliminating the need for expensive formation damage by-pass operations. The development of brine-based drill-in fluids opened up the opportunity to connect more effectively with hydrocarbon reserves by allowing the construction of long high-angle reservoir sections completed in open hole. Despite the advantages on offer, the industry was unable to exploit this novel technology in deep HPHT gas field developments until the mid-to late-1990's when drill-in fluids based on potassium and cesium formate brine became available in commercial volumes.Cesium formate brine was first used as a reservoir drilling fluid in the Huldra gas/condensate field in the North Sea in January 2001, and has now been used to drill a total of 29 deep HPHT gas wells. The information presented and reviewed in this paper confirms that the use of potassium and cesium formates as the sole weighting agents in reservoir drill-in fluids has enabled operators to enjoy the full economic benefits of creating low-skin open-hole completions in deep high-angle HPHT gas wells. The review also concludes that the use of these heavy formate brines as drill-in fluids over the past 10 years has facilitated the safe and efficient development of deep HPHT gas reserves by:• Virtually eliminating well control and stuck pipe incidents • Enabling the drilling of long high-angle HPHT wells with narrow drilling windows • Typically reducing offshore HPHT well completion times by 30 days or more • Improving the definition and visualization of the reservoirs • Eliminating the need for clean-ups, stimulation treatments or any other form of post-drilling well intervention to remove formation damage caused by the drilling fluid This has all been made possible by the operators' acceptance and adoption of the award-winning Chemical Leasing (ChL) and fluid management programmes that form the basis of their contracts with the sole producer of cesium formate brine.BP Devenick 1 385 4,560 <1 135 Petrobras El Campamento 1 650 --126This paper begins by providing a summary of these operations, field by field, and looks in some detail at the original drilling campaign in Huldra. It then lists some key highlights from ten years of drilling deep HPHT gas wells with barite-free cesium formate brine. The paper concludes that the use of cesium formate brine as a reservoir drill-in for deep gas field development enhances well construction efficiency, well safety and well productivity. Su...

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“…In addition to being used in the 7 Kvitebjørn wells, cesium/potassium formate brine has been the HPHT completion fluid of choice in all 6 Huldra wells 2 and in 7 Kristin wells 7 .…”

Section: Completing In Cesium Formatementioning

confidence: 99%

Drilling, Completion, and Openhole Formation Evaluation of High-Angle HPHT Wells in High-Density Cesium Formate Brine: The Kvitebjorn Experience, 2004-2006

Berg¹,

Pedersen²,

Lauritsen³

et al. 2007

Proceedings of SPE/IADC Drilling Conference

3

0

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TX 75083-3836 U.S.A., fax 1.972.952.9435. AbstractDrilling and completion fluids based on cesium formate brines were selected by Statoil for use in the development of the high pressure high temperature Kvitebjørn field. Cesium formate brine was selected primarily to minimize well control problems and maximize well productivity. These important benefits had been recognized by Statoil in previous HPHT drilling and completion operations over the past 5 years. The use of the same fluid system for both drilling and completion gives the additional benefits of simplified operations, reduced waste, and elimination of fluid incompatibility problems.The challenge on the Kvitebjørn field was to drill long deviated well paths through significant sequences of shales into reservoirs with pressures of up to 81 MPa (11,700 psi) and temperatures up to 155°C (311°F). So far the cesium formate brine has enabled the successful drilling, completion, and logging of 7 high angle HPHT production wells on Kvitebjørn, two completed with a cemented perforated liner and five with sand screens.Additionally, an extended-reach exploration well was drilled from the Kvitebjørn platform to the Valemon structure. The 705 m (2,313 ft) long reservoir section of this 7,380 m (24,213 ft) long well with an inclination of 69°, was successfully drilled with the same cesium formate fluid system.In all these wells the cesium formate brine system once again demonstrated clear performance benefits such as very low ECDs, moderate to high ROPs, good hole-cleaning, and excellent wellbore stability while logging. Quick, trouble-free, safe, and robust completion operations were also accomplished, and the wells that have been put on production show high production rates with low skin.Full open-hole formation evaluation of the Kvitebjørn reservoir has been carried out with LWD tools. The evaluation has been aided by the development of a novel logging interpretation solution for a LWD density tool, in which the extremely high photoelectric effect of cesium-rich filtrate plays a vital role. 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. The final interpretation result matches the core porosity from different lithologies in 3 different wells.Cesium formate brine has helped Statoil to achieve a remarkable record of zero well control incidents in all 15 HPHT drilling operations and 20 HPHT completion operations in the Kvitebjørn, Kristin, and Huldra fields over a period of 5 years.

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Drilling, Completion, and Openhole Formation Evaluation of High-Angle Wells in High-Density Cesium Formate Brine: The Kvitebjørn Experience, 2004–2006

Berg

¹

,

Pedersen

²

,

Lauritsen

³

et al. 2007

SPE/IADC Drilling Conference

View full text Add to dashboard Cite

TX 75083-3836 U.S.A., fax 1.972.952.9435. AbstractDrilling and completion fluids based on cesium formate brines were selected by Statoil for use in the development of the high pressure high temperature Kvitebjørn field. Cesium formate brine was selected primarily to minimize well control problems and maximize well productivity. These important benefits had been recognized by Statoil in previous HPHT drilling and completion operations over the past 5 years. The use of the same fluid system for both drilling and completion gives the additional benefits of simplified operations, reduced waste, and elimination of fluid incompatibility problems.The challenge on the Kvitebjørn field was to drill long deviated well paths through significant sequences of shales into reservoirs with pressures of up to 81 MPa (11,700 psi) and temperatures up to 155°C (311°F). So far the cesium formate brine has enabled the successful drilling, completion, and logging of 7 high angle HPHT production wells on Kvitebjørn, two completed with a cemented perforated liner and five with sand screens.Additionally, an extended-reach exploration well was drilled from the Kvitebjørn platform to the Valemon structure. The 705 m (2,313 ft) long reservoir section of this 7,380 m (24,213 ft) long well with an inclination of 69°, was successfully drilled with the same cesium formate fluid system.In all these wells the cesium formate brine system once again demonstrated clear performance benefits such as very low ECDs, moderate to high ROPs, good hole-cleaning, and excellent wellbore stability while logging. Quick, trouble-free, safe, and robust completion operations were also accomplished, and the wells that have been put on production show high production rates with low skin.Full open-hole formation evaluation of the Kvitebjørn reservoir has been carried out with LWD tools. The evaluation has been aided by the development of a novel logging interpretation solution for a LWD density tool, in which the extremely high photoelectric effect of cesium-rich filtrate plays a vital role. 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. The final interpretation result matches the core porosity from different lithologies in 3 different wells.Cesium formate brine has helped Statoil to achieve a remarkable record of zero well control incidents in all 15 HPHT drilling operations and 20 HPHT completion operations in the Kvitebjørn, Kristin, and Huldra fields over a period of 5 years.

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Drilling Fluids in an HP/HT Reservoir: Experiences With Three Different Systems on the Kristin Field Development

Cited by 10 publications

References 5 publications

Life Without Barite: Ten Years of Drilling Deep HPHT Gas Wells With Cesium Formate Brine

Life Without Barite: Ten Years of Drilling Deep HPHT Gas Wells With Cesium Formate Brine

Drilling, Completion, and Openhole Formation Evaluation of High-Angle HPHT Wells in High-Density Cesium Formate Brine: The Kvitebjorn Experience, 2004-2006

Drilling, Completion, and Openhole Formation Evaluation of High-Angle Wells in High-Density Cesium Formate Brine: The Kvitebjørn Experience, 2004–2006

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