30/11-8 S
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General information
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Wellbore history
GeneralWell 30/11-8 S was drilled on the Krafla prospect in the Fensal Sub-basin between the Frigg and Oseberg fields in the North Sea. The Krafla prospect is a horst structure with multiple reservoir levels. The main objective of the well was to prove a commercial hydrocarbon accumulation in the Upper and Middle Tarbert Formation with potential also for finding hydrocarbon accumulations in the deeper Etive and Ness Formations. A secondary well objective was to test a lead within the Paleocene Sele Formation (Hermod Sandstone). A geological sidetrack to the Krafla West structure would be considered if hydrocarbons and producible reservoir in the Brent Group were proven in the main well.Operations and resultsWell 30/11-8 S was spudded with the semi-submersible installation Ocean Vanguard on 20 March 2011 and drilled to TD at 4043 m (3844 m TVD) in the Early Jurassic Drake Formation. No significant problem was encountered in the operations. No shallow gas was detected. The well was drilled with seawater and hi-vis pills down to 813 m, with Performadrill WBM from 813 m to 2214 m, and with XP-07 OBM from 2214 m to TD.The Viking Group, Heather Formation came in at 3473 m (3285 m TVD). The upper part of Heather had water filled sandstones with oil shows. The Brent Group was encountered at 3528.9 m (3339.0 m TVD) which was 17 m TVD deeper than prognosed. The Upper and Middle Tarbert Formation reservoirs proved to be oil filled, but no OWC was encountered. The Ness Formation came in at 3732 m (3538 m TVD) and proved to be both condensate and water filled, but no contact was found. The Etive Formation was water filled without shows. Also the lead in the Sele Formation (Hermod Sandstone) proved to be water filled.Two cores were cut in the intervals 3481 to 3508 m (Heather Formation) and 3611 to 3666 m (Tarbert Formation). MDT fluid samples were taken at 3478 m (water), 3614.5 m (oil), 3555 m (oil), 3663.4 m (oil), 3748.2 m (condensate), and 3827.7 m (water). The oil samples had a contamination of 14 to 17 %, while the condensate sample was 30 % contaminated. All samples were taken with the MDT single probe.The well bore was plugged back for sidetracking on 20 May 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]810.004041.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom13481.03508.8[m ]23611.03666.4[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]83.1Cores 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 availableDST3555.000.00OILYESDST0.003614.50OILYESDST0.003614.50OILYESDST0.003748.20OILYESDST0.003748.22OILYES -
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 typeCONDUCTOR30189.036198.00.00LOTSURF.COND.20802.526813.01.46LOTINTERM.142202.717 1/22214.01.45LOTINTERM.9 5/83301.012 1/43308.01.85LOTOPEN HOLE4043.08 1/24043.00.00LOT -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CMR34503920DUAL OBMI33014035LWD - ARCVRES9 TELE1932208LWD - GVR6 ARCVRES6 PP33024043LWD - GVR8 ARCVRES8 VSON8 VADN822083302LWD - POWERPULSE129193MDT MINI-DST34763657MDT PP34773982MDT SA35553614MDT SA36633827MSIP CBL21413301MSIP CBL33014035PEX AIT HNGS33014048VSP7954000 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit1305157672178217822362333249825672567294333783433347434743529352937333976399339983998 -
Geochemical information
Geochemical information Document nameDocument formatDocument size [MB]txt0.00txt0.05 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured1731.3524.0Spud Mud1731.6040.0Kill Fluid- SW/Bentonite1941.6041.0Kill Fluid- SW/Bentonite1941.3523.0Spud Mud2291.6042.0Kill Fluid- SW/Bentonite3901.3524.0Spud Mud8031.3521.0Performadril10161.3529.0Performadril12141.3524.0Performadril15411.3525.0Performadril21341.4527.0XP-07 - #1421581.3531.0Performadril22081.3317.0XP-07 - #1422111.3416.0XP-07 - #1428031.3420.0XP-07 - #1433021.5528.0XP-07 - #1433021.3725.0XP-07 - #1435081.5527.0XP-07 - #1435971.5741.0XP-07 - #1436661.5530.0XP-07 - #1440431.5630.0XP-07 - #1440431.5529.0XP-07 - #14