7/7-2
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General information
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Wellbore history
GeneralWell 7/7-2 is located ca 8 km east of the UK border on the Jæren High in the North Sea. It was the second commitment well within the licence PL-148 and was designed to test the A-prospect, interpreted as a Late Jurassic channel sandstone. Planned TD was in Permian sediments or 3500 m, whichever came first.Operations and resultsWildcat well 7/7-2 was spudded with the semi-submersible installation Deepsea Bergen on 20 January 1992 and drilled to TD at 3430 m in the Permian Zechstein Group. The well took 100 days to drill and test, 20 days more than planned. This was mainly due to a 25% higher pore pressure than prognosed in the reservoir, resulting in a plug-back and 9 5/8" casing above reservoir, and not at TD as programmed. Other contributing factors were re-spud after lost stinger in 30" casing, two occasions of pulling BOP due to leakage and leak on swivel stem on top drive. The DSTs experienced severe difficulties with leakage and operation of down hole valves resulting in two mis-runs with testing string and a shortened DST no. 2. The well was drilled with CMC EHV and seawater down to 904 m, with KCl/PHPA/PAC from 904 m to 2744 m, and with ANCOTEMP mud from 2744 m to TD.The greater part of the prospect, the Late Jurassic Ula sandstone was encountered at 3327 m, and proved to be sandy. The Jurassic reservoir lithology consisted primarily of fine, well-sorted silica-cemented sandstone with poor visual porosity. Subsequent testing from 3348 - 3350 m showed a very tight formation, however testing from 3333 - 3342 m yielded oil. No oil-water contact was encountered, but organic geochemical analyses detected oil saturation in two intervals from the top of the reservoirs down to 3341, and from 3345 down to 3347 m.Four and a half m of shaley core was recovered in two cores from 3242 m to 3247 in the Mandal Formation. Good oil shows were observed in these cores. Organic geochemical analyses proved them to be excellent oil-prone source rock and with a maturity well within the oil window. Three cores were cut from 3338 m to 3363 m in the lower part of the Ula Formation and 17 m into the Triassic Smith Bank Formation. FMT pressures indicated a 0.766 g/cm3 oil gradient over the reservoir interval. Two FMT fluid samples were taken. Sample 4B at 3334 m recovered only mud filtrate. Sample 4C at 3335.4 m recovered 18.6 l mud filtrate and 200 ml of HC film.The well was permanently abandoned on 25 April 1992 as an oil discovery.TestingTwo drill stem tests were performed in the well, DST 1 in Triassic sandstones and DST 2 in sandstones of Late Jurassic age. In DST 1 a two-metre interval from 3348 m to 3350 m was perforated. No reservoir fluid was produced to surface, but oil was trapped between two valves in the test string and the string content was also reversed out and directed to tank. Approximately 15 litres of oil were recovered from the test.The well was perforated from 3333 m to 3342 m in DST 2. It produced 784 Sm3/d of oil through a 24/64" (9.53 mm) choke, with a wellhead pressure of 15218 kPa and a temperature of 80 °C. The gas-oil ratio was measured to 20 Sm3/Sm3 with a separator pressure of 2032 - 2150 kPa and a separator temperature of 65 - 71 °C. Maximum down hole temperature was 144 deg C. -
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]910.003422.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom13242.03243.0[m ]23243.03246.5[m ]33338.03348.6[m ]43350.03357.1[m ]53357.03368.4[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]33.6Cores 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 typeLaboratory1350.0[m]DCMILL1370.0[m]DCMILL1380.0[m]DCMILL1390.0[m]DCMILL1400.0[m]DCMILL1430.0[m]DCMILL1440.0[m]DCMILL1460.0[m]DCMILL1470.0[m]DCMILL1490.0[m]DCMILL1500.0[m]DCMILL1520.0[m]DCMILL1530.0[m]DCMILL1550.0[m]DCMILL1560.0[m]DCMILL1580.0[m]DCMILL1590.0[m]DCMILL1610.0[m]DCMILL1620.0[m]DCMILL1640.0[m]DCMILL1650.0[m]DCMILL1670.0[m]DCMILL1680.0[m]DCMILL1690.0[m]DCMILL1710.0[m]DCMILL1730.0[m]DCMILL1740.0[m]DCMILL1760.0[m]DCMILL1770.0[m]DCMILL1790.0[m]DCMILL1800.0[m]DCMILL1820.0[m]DCMILL1830.0[m]DCMILL1850.0[m]DCMILL1860.0[m]DCMILL1880.0[m]DCMILL1890.0[m]DCMILL1910.0[m]DCMILL1920.0[m]DCMILL1940.0[m]DCMILL1950.0[m]DCMILL1970.0[m]DCMILL1980.0[m]DCMILL2000.0[m]DCMILL2010.0[m]DCMILL2030.0[m]DCMILL2040.0[m]DCMILL2060.0[m]DCMILL2070.0[m]DCMILL2090.0[m]DCMILL2100.0[m]DCMILL2120.0[m]DCMILL2130.0[m]DCMILL2150.0[m]DCMILL2160.0[m]DCMILL2180.0[m]DCMILL2190.0[m]DCMILL2210.0[m]DCMILL2220.0[m]DCMILL2240.0[m]DCMILL2250.0[m]DCMILL2270.0[m]DCMILL2280.0[m]DCMILL2300.0[m]DCMILL2310.0[m]DCMILL2330.0[m]DCMILL2340.0[m]DCMILL2360.0[m]DCMILL2370.0[m]DCMILL2390.0[m]DCMILL2400.0[m]DCMILL2415.0[m]DCMILL2430.0[m]DCMILL2448.0[m]DCMILL2460.0[m]DCMILL2475.0[m]DCMILL2490.0[m]DCMILL2505.0[m]DCMILL2520.0[m]DCMILL2535.0[m]DCMILL2550.0[m]DCMILL2565.0[m]DCMILL2580.0[m]DCMILL2595.0[m]DCMILL2610.0[m]DCMILL2625.0[m]DCMILL2640.0[m]DCMILL2655.0[m]DCMILL2670.0[m]DCMILL2685.0[m]DCMILL2700.0[m]DCMILL2715.0[m]DCMILL3100.0[m]DCMILL3110.0[m]DCMILL3120.0[m]DCMILL3140.0[m]DCMILL3170.0[m]DCMILL3180.0[m]DCMILL3200.0[m]DCMILL3215.0[m]DCMILL3219.0[m]SWCSTATO3230.0[m]DCMILL3241.0[m]SWCSTATO3251.0[m]DCMILL3258.0[m]SWCSTATO3263.0[m]SWCSTATO3266.0[m]SWCSTATO3271.0[m]SWCSTATO3275.0[m]DCMILL3278.0[m]DCMILL3284.0[m]DCMILL3290.0[m]DCMILL3296.0[m]DCMILL3302.0[m]DCMILL3308.0[m]DCMILL3314.0[m]DCMILL3320.0[m]DCMILL3326.0[m]DCMILL3332.0[m]SWCSTATO3338.3[m]CSTATO3339.3[m]CSTATO3339.7[m]CSTATO3339.9[m]CSTATO3340.1[m]CSTATO3341.8[m]CSTATO3342.4[m]CSTATO3343.2[m]CSTATO3344.1[m]CSTATO3346.5[m]CSTATO3348.6[m]CMILL3358.7[m]CSTATO3377.0[m]DCMILL3386.0[m]DCMILL3395.0[m]DCMILL3404.0[m]DCMILL3413.0[m]DCMILL3422.0[m]DCMILL3428.0[m]DCMILL -
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 availableDSTTEST23333.003342.0015.04.1992 - 00:00YES -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit1051179247124712510266527232723285429753106310631263140315332403240328233273327334733473388 -
Composite logs
Composite logs Document nameDocument formatDocument size [MB]pdf0.60 -
Geochemical information
Geochemical information Document nameDocument formatDocument size [MB]pdf2.85 -
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]pdf20.42 -
Drill stem tests (DST)
Drill stem tests (DST) Test numberFrom depth MD
[m]To depth MD
[m]Choke size
[mm]1.0333333429.5Drill stem tests (DST) Test numberFinal shut-in pressure
[MPa]Final flow pressure
[MPa]Bottom hole pressure
[MPa]Downhole temperature
[°C]1.035.00015.00080Drill stem tests (DST) Test numberOil
[Sm3/day]Gas
[Sm3/day]Oil density
[g/cm3]Gas grav. rel.airGOR
[m3/m3]1.0787157400.8770.84020 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CBL VDL GR10002727CBL VDL GR15003283CDL CN SPL32853431CDL CN SPL GR27273304DIFL ACL GR27273303DIFL ACL MLL GR32853431DIFL ACL ZDL GR8862734DIPLOG32853432DIPS GR30753304FMT GR33163333FMT HP SG GR33343374FMT SG GR33350MWD - GR RES DIR1053430SWC33283410SWC GR31103282VELOCITY15153425VSP4703420 -
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 typeCONDUCTOR30165.036165.00.00LOTINTERM.20886.026886.02.05LOTINTERM.13 3/82728.017 1/22728.02.00LOTINTERM.9 5/83283.012 1/43283.02.05LOTLINER73420.08 1/23420.00.00LOT -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured19201.5534.0WATER BASED20771.5539.0WATER BASED20831.5534.0WATER BASED21821.5530.0WATER BASED23301.6024.0WATER BASED24481.5534.0WATER BASED25251.5532.0WATER BASED25861.5536.0WATER BASED27191.5532.0WATER BASED27441.6024.0WATER BASED28401.5530.0WATER BASED29491.5536.0WATER BASED30431.6041.0WATER BASED31001.6240.0WATER BASED31171.6740.0WATER BASED31211.6243.0WATER BASED31661.6240.0WATER BASED32421.6738.0WATER BASED32931.7048.0WATER BASED33121.7043.0WATER BASED33281.8726.0WATER BASED33301.9539.0WATER BASED33342.0426.0WATER BASED33381.9638.0WATER BASED -
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]pdf0.22