25/8-6
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General information
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Wellbore history
GeneralWell 25/8-6 was drilled to appraise the 25/8-5 S Discovery (Jotun) resource base and to confirm the OWC. The well is located close to the crest of the field, close to the western block boundary and PL103, who participated in the well.The well was drilled as a possible future vertical sub-sea producer.Operations and resultsAppraisal well 25/8-6 was spudded with the semi-submersible installation "Vildkat Explorer" on 19 May 1995 and drilled to TD at 2565 m. The well was drilled with seawater and hi-vis pills down to 1060 m and KCl/glycol mud from 1060 m to TD. Due to bad hole condition it was impossible to get wire line logs below 1460 m. The well was plugged back on 6 June and technically sidetracked& (25/8-6T2) from just below the 13 3/8" casing at 1073 m using "Lo-Tox" mineral oil based mud. This well bore built up to 13& at 1329 m and then dropped back to vertical at 1600 m, the well was kept vertical down through the reservoir. It was drilled to TD at 2577 m in the in the Early Paleocene Ekofisk Formation. Successful wire line logging was achieved in this well bore. The well confirmed oil in the Heimdal Formation with OWC at 2090 m TVD SS (2122.6 m RKB in the technical sidetrack) in clean sand.Eight cores were cut in the first well bore. Two were cut in shales of the Lista Formation (2054m to 2057 m and 2057 m to 2065 m). Due to very slow coring rate, coring was discontinued and a 12 1/4" hole was drilled down to 2077 m at the next core point. Six cores were subsequently cut in Heimdal Formation sandstone in the interval 2077 m to 2137.5 m. MDT fluid samples were taken in the Heimdal Formation at 2082.2 m (oil), 2122.1 m (oil), 2123.0 m (water + ca 15% oil), 2143.5 m (water), and 2145 m (water). After running TD logs, a string of 10-3/4" x 9-5/8" production casing was run and cemented, and the well was suspended on 27 June 1995 as an oil appraisal and potential future sub sea producer.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]1070.002565.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom12054.02056.0[m ]22057.02063.5[m ]32077.02084.2[m ]42084.52096.9[m ]52097.02098.9[m ]62100.02109.5[m ]72109.52119.0[m ]82119.02137.5[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]67.4Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
Core photos
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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 typeCONDUCTOR30214.036215.00.00LOTSURF.COND.13 3/81048.017 1/21050.00.00LOTINTERM.9 5/82577.012 1/42577.00.00LOT -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]AIT IPL HNGS ACTC PCD10482574AIT IPL HNGS ACTS10482574ARI GR10481060ARI GR10481060ARI IPL MSFL HNGS ACTS10481460ARI IPL MSFL HNGS ACTS10481060CBL VDL CCL GR12352474CST GR10692549EPT DSI GR ACTC10482570LWD - GR RES DEN NEU20282073LWD - GR RES DEN NEU20552207LWD - GR RES DEN NEU22112561MDT GR20822201MWD - GR RES2121055MWD - GR RES10482039MWD - GR RES10732258MWD - GR RES22582503MWD - GR RES25032571VSP GR1532570 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit153428598644644975118513101943194319962034207723692455248525272527 -
Geochemical information
Geochemical information Document nameDocument formatDocument size [MB]pdf0.70 -
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]pdf54.72 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured1941.13DUMMY10601.3216.0WATER BASED10631.3217.0WATER BASED12461.4356.0OIL BASED16671.4344.0OIL BASED20541.3525.0WATER BASED20771.3522.0WATER BASED20851.3521.0WATER BASED21001.3722.0WATER BASED21101.3723.0WATER BASED21381.3721.0WATER BASED22001.5331.0WATER BASED22111.3720.0WATER BASED22371.4351.0OIL BASED23201.4347.0OIL BASED23351.3720.0WATER BASED24731.3720.0WATER BASED25001.4343.0OIL BASED25071.4345.0OIL BASED25381.4350.0OIL BASED25651.5028.0WATER BASED25771.4345.0OIL BASED -
Palynological slides at the Norwegian Offshore Directorate
Palynological slides at the Norwegian Offshore Directorate Sample depthDepth unitSample typeLaboratory1200.0[m]DCSTRAT1320.0[m]DCSTRAT1340.0[m]DCSTRAT1380.0[m]DCSTRAT1400.0[m]DCSTRAT1440.0[m]DCSTRAT1460.0[m]DCSTRAT1480.0[m]DCSTRAT1510.0[m]DCSTRAT1540.0[m]DCSTRAT1560.0[m]DCSTRAT1580.0[m]DCSTRAT1610.0[m]DCSTRAT1640.0[m]DCSTRAT1670.0[m]DCSTRAT1700.0[m]DCSTRAT1730.0[m]DCSTRAT1760.0[m]DCSTRAT1800.0[m]DCSTRAT1840.0[m]DCSTRAT1870.0[m]DCSTRAT1900.0[m]DCSTRAT1965.0[m]DCSTRAT1980.0[m]DCSTRAT2030.0[m]DCSTRAT2054.0[m]DCSTRAT2058.0[m]DCSTRAT2063.0[m]DCSTRAT2078.0[m]DCSTRAT2084.0[m]DCSTRAT2092.0[m]DCSTRAT2107.0[m]DCSTRAT2108.0[m]CRRI2118.0[m]DCSTRAT2120.0[m]CRRI2124.0[m]CRRI2126.0[m]CRRI2127.0[m]DCSTRAT2128.0[m]CRRI2136.0[m]CRRI2137.0[m]DCSTRAT2148.0[m]CRRI2477.0[m]DCSTRAT2486.0[m]DCSTRAT2495.0[m]DCSTRAT2531.0[m]DCSTRAT2558.0[m]DCSTRAT2565.0[m]DCSTRAT