7/11-8
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General information
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Wellbore history
GeneralWildcat well 7/11-8 is located on the Cod Terrace of the North Sea, between the Mime Field to the South and the 7/8-3 Discovery to the North. The primary objective was to test Late Jurassic sandstones of the Ula Formation. Secondary objective of the well was to test continental sandstone reservoirs of Triassic age as seen in some nearby wells. Rocks of early and middle Jurassic age were thought to be absent at this location. The well was planned to be drilled to 4550 + 100 m, approximately 730 m into the Triassic to penetrate a strong intra Triassic reflector.Operations and resultsWell 7/11-8 was spudded with the semi-submersible installation Treasure Scout on 22 September 1983 and drilled to TD at 4750 m, almost one km into Triassic sediments. Gumbo problems and problems with the seal assembly were experienced when running the 13 3/8" casing. The well was drilled with seawater and pre-hydrated bentonite down to 620 m, with KCl polymer mud from 620 m to 3673 m, and with a bentonite/lignosulphonate/barite/lignite mud system from 3673 m to TD.The well encountered water bearing Triassic sandstones directly underlying lower Cretaceous shales. The Ula Formation was thus missing. No shows or other hydrocarbon indications were seen in the well. The intra Triassic marker was found at 4605 m in a shaly sequence.One core was cut in the Triassic sandstones from 3725 to 3743.95 m. The entire core consisted of greyish red to moderate brown sandstones, with occasional bands of greenish black to greenish grey sandstones. The RFT tool was run to obtain pressure points in the Triassic sands. The pressure data indicated a water gradient of 1.09 g/cm3 and no fluid sample was takenThe well was permanently abandoned on 12 December 1983 as a dry well.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]190.004750.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom13725.03744.0[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]19.0Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
Core photos
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Palynological slides at the Norwegian Offshore Directorate
Palynological slides at the Norwegian Offshore Directorate Sample depthDepth unitSample typeLaboratory4387.0[m]SWCRRI -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit102140428992899293229773028303930393168350436553676367637253725 -
Composite logs
Composite logs Document nameDocument formatDocument size [MB]pdf0.88 -
Geochemical information
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Documents – reported by the production licence (period for duty of secrecy expired)
Documents – reported by the production licence (period for duty of secrecy expired) Document nameDocument formatDocument size [MB]pdf17.57 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CBL VDL5371893CST28953703CST36824756HDT18963669HDT36774758ISF LSS GR SP1024757LDT CNL GR CAL45254758LDT CNL NGT CAL GR36774607LDT GR CAL6043703RFT37304723VSP VELOCITY3004759 -
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 typeCONDUCTOR30188.036188.00.00LOTSURF.COND.20605.026620.01.86LOTINTERM.13 3/81895.017 1/21910.01.89LOTINTERM.9 5/83673.012 1/43698.02.03LOTOPEN HOLE4750.08 3/84750.00.00LOT -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured4001.09waterbased15031.2143.011.0waterbased19391.4755.014.0waterbased23001.5254.012.0waterbased36791.5264.015.0waterbased47501.5552.017.0waterbased -
Pressure plots
Pressure plots The pore pressure data is sourced from well logs if no other source is specified. In some wells where pore pressure logs do not exist, information from Drill stem tests and kicks have been used. The data has been reported to the NPD, and further processed and quality controlled by IHS Markit.Pressure plots Document nameDocument formatDocument size [MB]pdf0.23