31/6-3
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General information
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Wellbore history
GeneralThe primary objective of the wildcat 31/6-3 was to assess possible hydrocarbon accumulations in the sands and sandstones of the Late Jurassic Sognefjord Formation. The target was prospect C, a structural trap in the southeastern corner of block 31/6 extending into the adjacent blocks 31/9, 32/4 and 32/7. The well was located on the apex of prospect C. The secondary objective of the well was to obtain Sedimentological data for the Sognefjord Formation sandstones in the well location. The well was planned to reach total depth at ca 2200 m, approximately 100 m into the Triassic.Operations and resultsThe well was spudded with the semi-submersible installation Nortrym on 1 November 1983. Repositioning of the rig had to be done due to anchoring problems. At 1950 m the drill string was hung off. Problems when attempting to retrieve the drill string resulted in pulling of BOP. When running in hole after 7 days, 10 m of fill was found. No other major problems occurred during drilling and the well reached planned TD at 2250 m in the Triassic Hegre Group. The well was drilled with seawater and hi-vis pills down to 618 m and with KCl/Polymer mud from 618 m to TD.The well encountered water-bearing sandstones in the Late/Middle Jurassic Sognefjord Formation as well as in the lower lying sandstones. No oil shows were noted on cores, sidewall cores or cuttings in any section of the well. Gas readings were low or nil throughout except for a 2.6% methane reading in a shallow sand unit at 414 m. The Sognefjord Formation sandstones (1511-1647 m) are very fine to fine, occasionally medium grained, micaceous, occasionally carbonaceous and slightly argillaceous. In places the sandstones grade into siltstones. They are well to moderately sorted and have fair visible porosity. The underlying Sognefjord, Fensfjord, and Krossfjord Formations (1647-1931.5m) are dominated by fine to medium, locally very fine or coarse grained sandstones which are often calcite cemented and have a fair visible porosity. Occasional interbeds of siltstone are also present together with some stringers of limestone, in the upper part yellow brown and very hard, becoming light grey and softer further down. The log evaluation gave a net sand thickness of 382,75 m out of a gross thickness of 420,5 m for the interval (1511 m to 1931.5 m) with an average porosity of 21.0% and an average water saturation of 96.1% (cut-off values used in the calculations were: 0<0,12, VSH>0,40). Eighteen FMT pressure test were performed over the interval 1513,5 m to 2146 m. From the pressure tests a water gradient of 0.1012 bar/m (1.033 g/cc) was calculated. A total of twelve cores were cut in the well. The cores recovered most of the Heather and Sognefjord Formations, and 25 m from the upper part of Fensfjord Formatio. No fluid samples were taken in the well.The well was permanently abandoned as a dry well on 26 December 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]410.002250.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom11495.01499.4[m ]21499.51509.0[m ]31509.01521.5[m ]41528.01528.6[m ]51533.51542.7[m ]61551.51565.4[m ]71565.51582.5[m ]81582.51601.3[m ]91601.51620.0[m ]101620.01638.5[m ]111638.51665.8[m ]121666.01694.1[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]178.3Cores 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 typeCONDUCTOR30399.036400.00.00LOTSURF.COND.20600.026618.01.39LOTINTERM.13 3/81360.017 1/21365.01.82LOTOPEN HOLE2250.012 1/42250.00.00LOT -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CDL CNL GR CAL399616CDL CNL GR CAL6001362CDL CNL GR CAL13502247DIFL LS BHC SP GR399619DIFL LS BHC SP GR6001362DIFL LS BHC SP GR13602250FMT15132146GR326619HRD6001364HRD13602243MLL13602250SL13502247SWC6001364SWC13701800SWC18052230VSP7002240 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit326508508550702808808823998998105811301370137014951511166917561932197419742042212521432195 -
Composite logs
Composite logs Document nameDocument formatDocument size [MB]pdf0.43 -
Geochemical information
Geochemical information Document nameDocument formatDocument size [MB]pdf6.70pdf1.19pdf7.09 -
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]pdf14.70 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured7001.2436.0water based10001.2441.0water based13001.2545.0water based14001.1339.0water based15101.2244.0water based17001.2244.0water based21001.2244.0water based -
Palynological slides at the Norwegian Offshore Directorate
Palynological slides at the Norwegian Offshore Directorate Sample depthDepth unitSample typeLaboratory790.3[m]SWCIKU800.2[m]SWCIKU805.2[m]SWCIKU807.7[m]SWCIKU815.2[m]SWCIKU840.2[m]SWCIKU880.2[m]SWCIKU895.2[m]SWCIKU910.2[m]SWCIKU940.3[m]SWCIKU995.2[m]SWCIKU1005.0[m]SWCIKU1015.0[m]SWCIKU1035.0[m]SWCIKU1075.0[m]SWCIKU1110.0[m]SWCIKU1150.0[m]SWCIKU1220.0[m]SWCIKU1245.0[m]SWCIKU1255.0[m]SWCIKU1270.0[m]SWCIKU1290.0[m]SWCIKU1300.0[m]SWCIKU1302.0[m]DCRRI1310.0[m]SWCIKU1315.0[m]SWCIKU1332.0[m]SWCIKU1336.0[m]SWCIKU1363.7[m]SWCIKU1370.0[m]SWCIKU1370.0[m]DCRRI1375.0[m]SWCIKU1380.0[m]SWCIKU1390.0[m]SWCIKU1400.0[m]SWCIKU1400.0[m]DCRRI1410.0[m]SWCIKU1420.0[m]SWCIKU1430.0[m]SWCIKU1440.0[m]SWCIKU1440.0[m]DCRRI1452.0[m]SWCIKU1461.0[m]SWCIKU1470.0[m]SWCIKU1480.0[m]DCRRI1481.0[m]SWCIKU1490.0[m]SWCIKU1530.0[m]DCRRI1551.5[m]CRRI1622.0[m]DCRRI1700.0[m]SWCIKU1710.0[m]SWCIKU1720.0[m]SWCIKU1720.0[m]DCRRI1730.0[m]SWCIKU1750.0[m]SWCIKU1760.0[m]SWCIKU1800.0[m]DCRRI1810.0[m]SWCIKU1820.0[m]SWCIKU1830.0[m]SWCIKU1840.0[m]SWCIKU1880.0[m]SWCIKU1880.0[m]DCRRI1910.0[m]SWCIKU1930.0[m]SWCIKU1940.0[m]SWCIKU1950.0[m]SWCIKU1960.0[m]SWCIKU1963.0[m]DCRRI1970.0[m]SWCIKU1980.0[m]SWCIKU2010.0[m]SWCIKU2018.5[m]SWC2030.0[m]DCRRI2040.0[m]SWCIKU2040.0[m]SWC2060.0[m]SWCIKU2084.0[m]SWC2105.0[m]SWCIKU2117.0[m]SWC2130.0[m]DCRRI2131.5[m]SWC2140.0[m]SWCIKU2162.0[m]SWC2175.0[m]SWCIKU2180.0[m]SWC2220.0[m]DCRRI