30/11-8 A
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General information
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Wellbore history
GeneralWell 30/11-8 A is a sidetrack to the 30/11-8 S Krafla well in the Fensal Sub-basin between the Frigg and Oseberg fields in the North Sea. Well 30/11-8 S found oil in the Middle Jurassic Tarbert Formation and condensate in the Middle Jurassic Ness Formation. Similar formations and fluids as found in the 30/11-8 S Krafla main structure were also expected in the nearby Krafla West structure and the main objective for the 30/11-8 A sidetrack, was thus to prove commercial hydrocarbon accumulation in the Upper and Middle Tarbert Formation and potentially in Lower Brent Group. The Krafla West reservoir is situated approximately 400 m deeper than the Krafla main.Operations and resultsWell 30/11-8 A was kicked off at 2135 m (2135 m TVD) in main well bore 30/11-8 S on 20 May 2011. It was drilled with the semi-submersible installation Ocean Vanguard to TD at 4475 m (4268 m TVD) in the Early Jurassic Drake Formation. No significant problem was encountered in the operations. The well was drilled with XP-07 OBM from kick-off to TD.The Viking Group, Heather Formation was encountered at 3671 m (3471.8 m TVD). At 3802 m (3580 m TVD) an Intra-Heather Formation sandstone sequence was encountered with oil down to ca 3825 m (3602 m TVD). The Brent Group, Tarbert Formation was encountered at 3914.6 m (3713.1 m TVD), which was 61.9 m TVD shallower than prognosed. The Upper and Middle Tarbert Formation reservoirs proved to be condensate filled. The condensate-water contact is estimated at 4017 m (3791.6 m TVD). The Ness and Etive Formations were water filled. Apart from shows in the petroleum-bearing reservoirs the cutting shows descriptions from 4065 - 4083 m MD in the Tarbert Formation had strong yellowish direct fluorescence and very slow streaming milky white cut fluorescence.One core was cut from 3960 to 3993.5 m in the Tarbert Formation consisting of mainly sandstone and claystone. Depth shift of the core relative to the logs was 2.9 m down. MDT fluid samples were taken at 3810.1 m (oil), 3948.9 m (condensate), 3991.7 m (condensate), and at 4007 m (water).The well was permanently abandoned on 3 July 2011 as an oil and condensate discovery.TestingNo drill stem test was performed. -
Cuttings at the Norwegian Offshore Directorate
Cuttings at the Norwegian Offshore Directorate Cuttings available for sampling?YESCuttings at the Norwegian Offshore Directorate Cutting sample, top depth [m]Cutting samples, bottom depth [m]2135.004475.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom13960.03993.6[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]33.6Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
Oil samples at the Norwegian Offshore Directorate
Oil samples at the Norwegian Offshore Directorate Test typeBottle numberTop depth
MD [m]Bottom depth
MD [m]Fluid typeTest timeSamples availableDST3991.700.00OIL17.02.2011 - 00:00YESDST3948.900.00OIL17.02.2011 - 00:00YESDST3810.100.00OIL17.02.2011 - 00:00YES -
Casing and leak–off tests
Casing and leak–off tests Casing typeCasing diam.
[inch]Casing depth
[m]Hole diam.
[inch]Hole depth
[m]LOT/FIT mud eqv.
[g/cm3]Formation test typeINTERM.9 5/83557.012 1/43564.02.25LOTOPEN HOLE4475.08 1/24475.00.00LOT -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CMR HNGS37944450DUAL OBMI DSI35704400LWD - ARCVRES6 STET TELE39604475LWD - ARCVRES8 TELE21353960MDT HC SA38103948MDT HC WSA39484007MDT PP38034423PEX AIT35554480PEX DSI20223558USIT CBL30653508 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit1304037672178217822372335251125812581294034813557367136713915391541594412442544364436 -
Geochemical information
Geochemical information Document nameDocument formatDocument size [MB]txt0.00txt0.06 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured21531.4529.0XP-07 - #1433951.8237.0XP-07 - #1435581.5328.0XP-07 - #1435691.6429.0XP-07 - #1439601.6529.0XP-07 - #1439931.7030.0XP-07 - #1442351.7434.0XP-07 - #1444751.7940.0XP-07 - #14