31/2-2
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General information
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Wellbore history
GeneralWell 31/2-2 was drilled some 4 km east of the discovery well 31/2-1 on seismic line 79-416 at SP 200. The concession requirement for the wells were complete penetration of the prospective Jurassic sequence and terminate in Triassic or older. The particular objectives of well 31/2-2 were: to evaluate lateral variation of reservoir parameters eastwards on the flank of the structure: to test the zone of oil shows seen in 31/2-1 in better reservoir conditions, to test the gas accumulation in a down-dip location: to evaluate the nature of the seismic flatspot, and to provide geological calibration of seismic reflectors above the reservoir for improved regional evaluation.Operations and resultsWell was spudded with the semi-submersible installation West Venture on 27 February 1980 and drilled to TD at 1857 m in the Middle Jurassic Krossfjord Formation. The 36" hole was drilled without incident to 433 m using seawater with viscous pills spotted on connections. From 422 m to 433 m hard drilling was experienced. This was interpreted as a boulder bed similar to that found at a comparable depth in the previous 31/2-1 well. Problems were encountered with the stability of the temporary guide base, and the well had to be abandoned. The rig was moved NE 25 m and re-spudded on 29 February. The well was drilled with seawater and hi-vis pills down to 800 m, and with gypsum/lignosulphonate mud from 800 m to TD.Top reservoir (Sognefjord Formation) came in at 1544 m and was gas bearing down to a gas/oil contact at 1579 m, and oil-bearing from 1579 m down to an oil/water contact at 1591 m. Both contacts were clearly defined on logs, the gas/oil contact was confirmed by RFT pressure gradients, and moveable oil was confirmed by RFT sampling at 1587.5 m and 1590 m. Gas samples were obtained from 1548 m and 1571 m. Weak oil shows began at 1561 m in the gas zone, strong shows with stained and bleeding cores and a paraffinic smell were observed in the oil zone. Oil shows ceased at 1602 m.Coring started at 1515 m in the Draupne Formation and terminated below the oil-water contact. A 120 m interval was cored with 94.2 m of core in 13 cores recovered at surface.After coring and logging of the Late Jurassic sandstones the well was suspended at the 9 5/8 casing shoe and the rig towed to Bergen for inspection and repairs on 22 April 1980.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]490.002600.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom11515.01521.1[m ]21525.01527.0[m ]31535.01547.6[m ]41553.01560.0[m ]51560.01569.0[m ]61569.01578.0[m ]71578.01581.0[m ]81585.01598.0[m ]91598.01603.6[m ]101604.01606.4[m ]111608.01617.0[m ]121617.01626.0[m ]131626.01632.5[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]94.2Cores 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 typeLaboratory870.0[m]DCGEOCH900.0[m]DCGEOCH930.0[m]DCGEOCH960.0[m]DCGEOCH990.0[m]DCGEOCH1167.0[m]DCGEOCH1203.0[m]DCGEOCH1233.0[m]DCGEOCH1263.0[m]DCGEOCH1287.0[m]DCGEOCH1317.0[m]DCGEOCH1347.0[m]DCGEOCH1377.0[m]DCGEOCH1398.0[m]DCGEOCH1428.0[m]DCGEOCH1455.0[m]DCGEOCH -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit35565065070311241124120513031374142414241431147014701545166517001848 -
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]pdf5.70pdf8.88pdf2.76pdf1.32pdf2.48pdf0.51pdf0.17pdf0.27pdf0.77pdf0.75pdf6.21pdf19.85pdf14.80pdf12.53pdf0.16pdf12.76pdf12.64pdf11.26pdf6.20pdf0.84pdf0.57pdf0.07pdf8.08pdf3.79pdf5.02pdf3.96pdf8.36pdf28.43pdf24.38pdf0.48pdf0.70pdf3.90pdf1.52pdf0.06pdf0.03pdf0.02pdf0.03pdf0.02pdf0.04pdf2.58pdf1.22pdf0.79pdf2.78pdf0.09pdf0.89pdf1.99pdf0.55pdf1.37pdf0.86pdf1.75pdf1.83pdf0.13pdf1.48pdf0.30pdf0.28pdf7.44pdf10.03pdf6.68pdf11.62pdf8.95pdf8.22pdf2.42pdf3.02pdf0.77pdf9.04pdf1.79pdf1.33pdf1.07pdf0.32pdf0.30pdf0.70pdf0.19 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CBL CCL GR7751825CBL GR CCL3541844FDC CNL GR CAL430797FIT15061506FIT15951595HDT14691855HDT18452590ISF BHC GR SP430809ISF BHC GR SP18002590LSS CTR18452590LSS GR14691855MSFL DLL SP CAL14691855RFC CNL GR CAL18002590RFT10RFT28VELOCITY00 -
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 typeCONDUCTOR30398.036400.00.00LOTSURF.COND.20768.026780.01.72LOTINTERM.13 3/81438.017 1/21448.01.64LOTINTERM.9 5/81817.012 1/41826.01.65LOTOPEN HOLE2568.08 1/22568.00.00LOT -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured7081.2241.0seawater10001.2249.0seawater14081.2250.0seawater16241.2645.0seawater -
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]PDF0.20