15/5-4
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General information
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Wellbore history
GeneralWell 15/5 4 was drilled on a structure that straddles the border between the U.K. and the Norwegian sector of the North Sea. Hydrocarbons were proven in the structure by three earlier wells drilled in the UK sector (U.K. 16/13a-3, 16/13a-4, and 16/13a-5). Well 16/13a-4 penetrated a gas cap at the top of the structure and an oil column down to base reservoir. The other two wells penetrated an oil zone and a water leg. The objective of well 15/5-4 was to assess the extension of hydrocarbon bearing Sele Formation sand towards the east into PL048. The well position was chosen for possible use as a producer in the event of a positive appraisal. Prognosed total depth was 2300 m.Operations and resultsAppraisal well 15/5-4 was spudded by the semi submersible installation Vildkat Explorer on 6 June 1991 and drilled to TD at 2300 m in rocks of the Paleocene Heimdal Formation. No shallow gas was observed on the predicted sand/gas levels. Drilling proceeded without any significant problems. The well was drilled with spud mud down to 1027 m and with KCl/polymer mud from 1027 m to TD.Thin sands of the Sele Formation were encountered at 2120 m and had good oil shows. The reservoir thickness was calculated to 7.5 m. The sandstones of the Heimdal Formation were penetrated below the oil/water contact and were totally water wet. Weak oil shows was described on sidewall cores from claystone at 1909 m in the Frigg Formation and sandstone at 2182 m in the Lista Formation.A total of six cores were cut from 2106 m to 2147 m over the reservoir section. RFT fluid samples were attempted at 2125.1 m, 2125.3 m, 2125.8 m, and 2129.5 m. Sampling suffered from sand plugging and only the samples from run 1C (2129.5 m) contained traces of oil.The well was permanently abandoned on 3 July 1991 as a well with oil shows.TestingOne DST test was performed over the interval 2123.4 to 2135.9 m in the Sele Formation. Water was produced, but not to surface. -
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]1040.002300.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom12106.02124.8[m ]22124.02129.0[m ]32129.02132.0[m ]42132.02145.9[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]40.7Cores 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 typeCONDUCTOR30230.036231.00.00LOTINTERM.13 3/81012.017 1/21027.01.35LOTINTERM.9 5/82248.012 1/42300.00.00LOT -
Drill stem tests (DST)
Drill stem tests (DST) Test numberFrom depth MD
[m]To depth MD
[m]Choke size
[mm]1.02124213625.4Drill stem tests (DST) Test numberFinal shut-in pressure
[MPa]Final flow pressure
[MPa]Bottom hole pressure
[MPa]Downhole temperature
[°C]1.068Drill stem tests (DST) Test numberOil
[Sm3/day]Gas
[Sm3/day]Oil density
[g/cm3]Gas grav. rel.airGOR
[m3/m3]1.0 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CST GR15012194DIL SDL LDL NGL SP CAL AMS10072254DLL MSFL GR CAL AMS20682226FMS4 GR CAL AMS10072229MWD - GR RES DIR1452298RFT HP GR18322134RFT HP GR21252143RFT HP GR21252206VSP8002235 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit145782896158620722072212021732198 -
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]pdf1.77pdf2.96 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured1861.05WATER BASED2311.05WATER BASED5971.05WATER BASED10271.20WATER BASED10271.20WATER BASED13701.1013.0WATER BASED17021.1815.0WATER BASED19111.2319.0WATER BASED21061.2318.0WATER BASED21151.2519.0WATER BASED21291.2517.0WATER BASED21351.2519.0WATER BASED21471.2618.0WATER BASED22941.2520.0WATER BASED23001.2620.0WATER BASED -
Palynological slides at the Norwegian Offshore Directorate
Palynological slides at the Norwegian Offshore Directorate Sample depthDepth unitSample typeLaboratory1190.0[m]DCRRI1200.0[m]DCRRI1220.0[m]DCRRI1230.0[m]DCRRI1250.0[m]DCRRI1260.0[m]DCRRI1280.0[m]DCRRI1290.0[m]DCRRI1310.0[m]DCRRI1320.0[m]DCRRI1340.0[m]DCRRI1350.0[m]DCRRI1370.0[m]DCRRI1380.0[m]DCRRI1501.0[m]SWCNH1530.0[m]SWCNH1561.0[m]SWCNH1580.0[m]DCRRI1593.0[m]SWCNH1610.0[m]DCRRI1630.0[m]SWCNH1697.0[m]SWCNH1718.0[m]SWCNH1738.0[m]SWCNH1754.0[m]SWCNH1760.0[m]DCRRI1778.0[m]SWCNH1800.0[m]SWCNH1824.0[m]SWCNH1850.0[m]DCRRI1856.0[m]SWCNH1874.0[m]SWCNH1909.0[m]SWCNH1945.0[m]DCRRI1954.0[m]SWCNH1975.0[m]DCRRI1983.0[m]SWCNH2000.0[m]SWCNH2020.0[m]DCRRI2032.0[m]SWCNH2058.0[m]SWCNH2071.0[m]SWCNH2085.0[m]SWCNH2098.0[m]SWCNH2115.0[m]CRRI2120.0[m]CRRI2124.0[m]CRRI2129.0[m]CRRI2134.0[m]CRRI2136.0[m]CRRI2139.0[m]CRRI2145.0[m]CRRI2157.0[m]DCRRI2165.0[m]DCRRI2172.0[m]SWCNH2182.0[m]SWCNH2190.0[m]DCRRI2194.0[m]SWCNH2205.0[m]DCRRI2210.0[m]DCRRI2220.0[m]DCRRI2225.0[m]DCRRI2235.0[m]DCRRI2240.0[m]DCRRI2250.0[m]DCRRI2255.0[m]DCRRI2265.0[m]DCRRI2270.0[m]DCRRI2280.0[m]DCRRI2285.0[m]DCRRI2295.0[m]DCRRI2300.0[m]DCRRI