3/7-8 S
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General information
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Wellbore history
GeneralWell 3/7-8 S was drilled on the Trym South prospect between the Norwegian Trym field and the Danish Lulita Field in the North Sea. The primary objectives were to prove hydrocarbons in the Sandnes and Bryne formations, to define the fluid contacts and to obtain representative fluid samples from the reservoirs. A secondary objective was to investigate the presence of hydrocarbons in the Palaeocene Maureen Formation.Operations and resultsWildcat well 3/7-8 S was spudded with the jack-up installation Mærsk Giant on 9 December 2012 and drilled to TD at 4188 m (3733 m TVD) in the Permian Zechstein Group. The well was drilled vertical down to 1123 m. From there, inclination was built up to a sail angle of 41° at ca 1700 m. From ca 2512 m, the inclination was dropped to vertical again from ca 3800 m. Apart from stuck conductor in the top hole, requiring a re-spud, there were no significant problems encountered in the operations. The well was drilled with seawater down to 202.5 m, with bentonite/polymer mud from 202.5 m to 1126 m, and with Versatec oil based mud from 1126 m to TD.The Maureen Formation was encountered at 3302 m, but was water-wet. Top Sandnes Formation Sandstone was encountered at 3891.5 m (3435.8 m TVD). The Sandnes and underlying Bryne formations contained a 36 m TVD oil column with an 85 m TVD gas cap. The net/gross for the hydrocarbon bearing interval was 0.51. A GOC was established at 3977 m (3521.4 m TVD) and the OWC at 4012.9 m (3557.3 m TVD). Pressure data showed four clearly differently pressured zones through the hydrocarbon bearing reservoir, separated by coals and shaley barriers as seen on the well logs. Fair to good oil shows were recorded between 3891 m and 4000 m and trace to poor shows were recorded from 4000 to 4040 m. Otherwise no oil shows above the oil base in the mud were detected in the well.Three cores were cut in the Sandnes and Bryne formations from 3890 to 4039 m with 100% recovery. The core to log depth shifts for cores 1, 2, and 3 are 3.0 m, 3.4 m, and 3.6 m, respectively. RCX fluid samples were taken at 3933.5 m (gas), 3952 m (gas), 3975.5 m (gas), 3979.5 m (oil), 4005.5 m (oil), 4005.7 m (oil), and 4042.5 m (water).The well was permanently abandoned on 3 March 2013 as an oil and gas 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]210.004187.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom13890.03944.4[m ]23944.53996.7[m ]33996.74039.8[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]149.7Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
Palynological slides at the Norwegian Offshore Directorate
Palynological slides at the Norwegian Offshore Directorate Sample depthDepth unitSample typeLaboratory3820.0[m]DCFUGRO3857.0[m]DCFUGRO3884.0[m]DCFUGRO3899.0[m]CFUGRO3907.7[m]CFUGRO3921.0[m]CFUGRO3959.8[m]CFUGRO3990.0[m]CFUGRO4020.9[m]CFUGRO4049.0[m]DCFUGRO4061.0[m]DCFUGRO4124.0[m]DCFUGRO4160.0[m]DCFUGRO -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit1101481320632063235325233023353335334943725379637963800380138013892389239494148 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]EXPL GXPL ORIT DSL38394184MED - NBGR RES DI GR PWD RES38443890MREX XMAC ORIT DSL1094192MWD - DI110202MWD - DI PWD2021126MWD - GR DI PWD RES SON2021100MWD - GR DI PWD RES SON11263844MWD - GR DI RES NEU DEN SON STET38904188RCX CPS39334005RCX PS39754042 -
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 typeCONDUCTOR30197.536202.50.00SURF.COND.201123.0241126.00.00INTERM.13 3/82365.0162370.01.94LOTINTERM.9 5/83840.012 1/43844.02.09LOTOPEN HOLE4188.08 1/24188.00.00 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured2021.50seawater11261.20BentonitWBM40001.50VersatecOBM