30/11-9 A
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General information
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Wellbore history
GeneralWell 30/11-9 A is a geologic sidetrack to well 30/11-9 S. It was drilled to test the Askja East prospect in the Fensal Sub-basin, about 35 km south of the Oseberg Sør installation in the North Sea. The Askja East prospect is situated in a separate fault block to the 30/11-9 S Askja West discovery. The primary objective for 30/9-11 A was to prove petroleum in the Middle Jurassic Tarbert Formation. The secondary exploration target was to prove petroleum in reservoir rocks in the Middle Jurassic Ness and Etive formations.Operations and resultsWildcat well 30/11-9 A was kicked off at 1401 m in main well 30/11-9 S on 13 November 2013. It was drilled with the semi-submersible installation Ocean Vanguard to TD at 4054 m in the Middle Jurassic Ness Formation. Problems with the Ocean Vanguard DDM caused some downtime and slow drilling in periods, but otherwise no significant problem was encountered in the operations. The well was drilled with XP-07 oil based mud from kick-off to TD.The top of the expected main reservoir, Tarbert Formation came in as prognosed at 3615 m (3252 m TVD). Based on pressure gradients and fluid sampling, oil was present in two differently pressured compartments within the upper part of the Tarbert Formation. The upper reservoir contained oil from 3615 m (3252 m TVD) down to an oil-water contact indicated at 3636 m (3272 m TVD). The lower reservoir contained oil from 3745 m (3374.5 m TVD) down to an oil-water contact indicated at 3771 m (3400 m TVD). Oil shows (fluorescence) were described on sandstones in between these two reservoirs. The lower part of Tarbert Formation and the Ness Formation were water bearing. The Etive Formation was not drilled since the Ness Formation was water bearing.Three cores were cut in 30/11-9 A, all three with 100% recovery. Core 1 was cut from 3613.6 to 3667 m, while cores 2 and 3 were cut and recovered the whole interval from 3738.5 to 3848 m. The core to log depth shift was ca +4.4 m for all three cores. MDT fluid samples were taken at 3619.2 m (oil), 3749.0 m (oil), 3754.9 m (oil), 3771.9 m (water), and 3837.0 m (water).The well was permanently abandoned on 9 January 2014 as an oil 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]1410.004054.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom13613.63667.8[m ]23738.53792.6[m ]33792.63848.0[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]163.7Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
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 5/83491.012 1/43491.01.91LOTOPEN HOLE4054.08 1/24054.00.00 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]2XOBMI GPIT NGI HNGS GR34913950AIT PPC MSIP PPC PEX32894054CBL USIT GYRO28363421MWD LWD - PD ARC8 TELE12893512MWD LWD - PD X6 PERI15 TELE24744054PS HY PO LFA SC1 MS PC CMR GR36193982SC PO PA PQ HY PO SC GR CMR35503815SCEX PO PQ HY LFA SC1 MS PC GR36193755 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit13213253769769714291481219522992299235123762575268628002800313633493349342434243474361536153896 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured14211.4328.0XP-07 - Yellow28201.4531.0XP-07 - Yellow32281.4523.0XP-07 - Yellow34441.3025.0XP-07 - Yellow35121.2714.0XP-07 - Yellow36131.2720.0XP-07 - Yellow40541.2925.0XP-07 - Yellow