7120/12-3
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General information
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Wellbore history
GeneralWell 7120/12-3 is located in the Hammerfest Basin, south of the Snøhvit area. The primary objective was to test a sandstone reservoir of Middle to Early Jurassic age on a structure (Alke North) separate from the Alke Structure tested in well 7120/12-1 and 7120/12-2. A secondary objective was to test Middle Triassic sandstones, providing the Jurassic reservoir proved a gas column greater than 60 m. The well was planned to be drilled to 2498 + 30 m or to 3312 +100 m if the Jurassic test was positive.Operations and resultsWildcat well 7120/12-3 was spudded with the semi-submersible installation on 16 March 1983 and drilled to TD at 2523 m in the Late Triassic Fruholmen Formation. Swelling shales and some tight hole problems occurred in the 17 1/2" section; otherwise no significant problems were encountered during drilling. The well was drilled using seawater / bentonite / hi-vis pills down to 605 m and with a gypsum / polymer mud from 605 m to TD.The Middle to Early Jurassic sandstone reservoir was found gas bearing from 2157.5 to 2182.5 m (upper part of Stø Formation) where the gas/water contact was established. The reservoir consisted of very fine to fine, relatively homogeneous and clean sandstones made up of clear quartz with traces of mica, glauconite and carbonaceous material. From wire line logs the net pay was calculated to be 24 m, with an average porosity of 17 % and an average water saturation of 17 %. Traces of very weak shows were described from cuttings and sidewall cores between 1945 m to 2148.5 m in shales of the Late Jurassic Hekkingen and Fuglen Formation, reflecting the high organic content of these shales. Direct shows were only seen in the lower part of the gas-bearing reservoir from 2170 m to 2182.5 m. They appeared on sandstones as traces of dull yellow fluorescence with weak slow streaming dull yellow to white crush cut, no stain or residue were detected. Very weak shows were detected in shales from 2260 m (cuttings) and 2505,5 m (side wall core).One core was taken in the water zone in the Stø Formation from 2195 to 2213 m. The recovery was 100 %, and the lithology was fine to very fine-grained sandstones, moderately silica cemented with irregular argillaceous laminae. RFT pressure recordings and sampling were successfully performed over the reservoir interval. The gas gradient was found to be 0.029 bar/m equivalent to a density of 0.29 g/cm3. The underlying water gradient was 0.109 bar/m corresponding to a density of 1.12 g/cm3. Three RFT segregated samples were taken, at 2160 m, 2172.5 m, and 2178.5 m, all recovered dry gas and minor amounts of water/mud filtrate.Due to the small gas column in the Jurassic the well was not deepened to test the Middle Triassic sandstones. It was permanently abandoned as a gas discovery on 5 May 1983.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]280.002523.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom12195.02213.0[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]18.0Cores 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 typeLaboratory695.0[m]SWCIKU709.0[m]SWCIKU721.0[m]SWCIKU747.0[m]SWCIKU778.5[m]SWCIKU907.5[m]SWCIKU935.0[m]SWCIKU1019.0[m]SWCIKU1040.0[m]SWCIKU1207.0[m]SWCIKU1225.0[m]SWCIKU1241.0[m]SWCIKU1292.5[m]SWCIKU1317.0[m]SWCIKU1355.0[m]SWCIKU1380.5[m]SWCIKU1409.0[m]SWCIKU1465.0[m]SWCIKU1496.0[m]SWCIKU1502.0[m]SWCIKU1506.0[m]SWCIKU1539.0[m]SWCIKU1557.0[m]SWCIKU1566.0[m]SWCIKU1571.0[m]SWCIKU1586.0[m]SWCIKU1622.0[m]SWCIKU1647.0[m]SWCIKU1696.5[m]SWCIKU1723.3[m]SWCIKU1762.0[m]SWCIKU1770.0[m]SWCIKU1781.0[m]SWCIKU1796.0[m]SWCIKU1830.0[m]SWCIKU1856.0[m]SWCIKU1886.0[m]SWCIKU1894.0[m]SWCIKU1903.0[m]SWCIKU1939.0[m]SWCIKU1945.0[m]SWCIKU1951.5[m]SWCIKU1957.5[m]SWCIKU2048.0[m]SWCIKU2097.5[m]SWCIKU2105.9[m]SWCIKU2130.0[m]SWCIKU2140.0[m]SWCIKU2148.5[m]SWCIKU2155.0[m]SWCIKU2195.8[m]CIKU2199.3[m]CIKU2206.9[m]CIKU2210.0[m]CIKU2211.4[m]CIKU2251.0[m]SWCIKU2458.0[m]SWCIKU2513.5[m]SWCIKU2523.0[m]SWCIKU2523.0[m]DCOD -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit208387387738738864864142217781946214221582158222023422395 -
Composite logs
Composite logs Document nameDocument formatDocument size [MB]pdf0.40 -
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]pdf5.30pdf1.37 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CBL VDL2251480CST6951506CST15071957CST19822523DLL GR21402520HDT5852522ISF LSS GR2681510ISF LSS GR22302524ISF MSFL LSS GR14872265LDT CNL GR14872523LDT GR2681512RFT21722172RFT21782178RFT21802218VELOCITY3822522 -
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 typeCONDUCTOR30269.036274.00.00LOTSURF.COND.20586.026605.01.82LOTINTERM.13 3/81485.017 1/21515.01.65LOTOPEN HOLE2523.012 1/42523.00.00LOT -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured2741.03spud mud5851.1042.06.0spud mud11301.2050.011.0water based15151.2560.017.0water based21401.3555.010.0water based25231.3550.010.0water 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]pdf0.27