2/5-9
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General information
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Wellbore history
Well 2/5-9 is located in the vicinity of the 2/5-3 Sørøst Tor and the 2/5-4discoveries on the Steinbit Terrace in the southern North Sea. The main objective was to test the hydrocarbon potential of the Late Jurassic sands in a rotated fault block, designated as the Magne structure. Secondary objectives were to determine the reservoir quality of any sand prone intervals penetrated in the well, to determine the Jurassic stratigraphy in this easterly part of the Central Graben, and to establish seismic well ties into prospective acreage surrounding the Magne prospect.Operations and resultsWildcat well 2/5-9 was spudded with the semi-submersible installation West Vanguard on 10 September 1991 and drilled to TD at 5460 m (5443 m TVD) in the Late Jurassic Haugesund Formation. Pore pressure reached a maximum estimated value of 15.9 ppg at TD. The well was kept vertical down to 4350 m, where angle started to build up to a maximum of 12.5 deg deviation at 4744 m. The deviation at TD was 10.4 deg. The well took 131 days to to complete, from spud to abandonment. A total of 36.8 days was unscheduled events, of which rig repair, malfunction of drilling equipment, and hole problems were the major contributors. Also an additional deepening from the authorized TD at 5337 m to 5460 m in order to penetrate a reflector identified by wire line seismic logging (QSST checkshot) increased the pre-drill schedule. The well was drilled with seawater and bentonite pills down to 960 m, with KCl polymer mud from 960 m to 2880 m, and with PHPA/KCl polymer mud from 2880 m to TD. No shallow gas zones were penetrated in the well.The top Rogaland at 3126 m and top Shetland Group at 3259 m came in 10 m and 17 m shallow to prognosis, respectively. The top Early Cretaceous at 4083 m came in 64 m shallow to prognosis and was 54 in thick, 31 m thicker than prognosed. The top Jurassic Tyne Group came in at 4137 m, 33 m shallow to prognosis, and after that a total of 1323m of Jurassic section were penetrated without encountering any sandstone. The Mandal Formation and uppermost section of the Farsund Formation were absent, represented by the Base Cretaceous unconformity.In the Nordland and Hordaland Groups very poor oil shows were noted in silty claystones and shales at 1215 - 1250 m and at 2740 - 2800, respectively. An oil bearing section of 33.5 m consisting of interbedded marly limestones, claystones and thin sandstone stringers was encountered at 4074 - 4107.5 m in the lowermost Shetland Group and uppermost Cromer Knoll Group. Good shows were recorded in the section, but it was tight and non-productive with a net pay of only 8.6 m. Weak shows were recorded also throughout the shales of the Tyne Group, but these are interpreted as in-situ generated hydrocarbons typical of these source rocks, when sufficiently buried.No cores were cut and no wire line fluid samples were taken.The well was permanently abandoned on 18 January 1992 as a dry well with shows.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]970.005460.00 -
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 typeCONDUCTOR30187.036190.00.00LOTINTERM.20950.026960.01.75LOTINTERM.13 3/82872.017 1/22880.02.02LOTINTERM.9 5/84515.012 1/44525.02.23LOTOPEN HOLE5460.08 1/25460.00.00LOT -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]FMS GR28724532FMS GR45185342GR CNL LDL45185342GR DLL LSS9502880GR LDL CNL NGT AS28724532GR MSFL DLL LDL AS28724150GR MSFL PIL40004532GR PIL AS45185342GR PIL AS52755468QSST10222875QSST39784500QSST45005320RFT33424314WA VSP24222650ZO VSP25924140 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit91170731263126314831953243325932593378370340794081408340834108413741374313 -
Composite logs
Composite logs Document nameDocument formatDocument size [MB]pdf0.97 -
Geochemical information
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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]pdf2.70pdf23.95 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured961.03WATER BASED1451.2010.0WATER BASED1901.2010.0WATER BASED9601.02WATER BASED19031.5331.0WATER BASED19091.6225.0WATER BASED21081.6226.0WATER BASED21851.6238.0WATER BASED22331.7046.0WATER BASED23471.7237.0WATER BASED24161.7050.0WATER BASED24231.7038.0WATER BASED28491.7464.0WATER BASED28801.7425.0WATER BASED28801.7524.0WATER BASED28971.6718.0WATER BASED30701.6827.0WATER BASED37301.6124.0WATER BASED38601.6130.0OIL BASED39781.7431.0WATER BASED40901.8033.0WATER BASED41501.8032.0WATER BASED41711.8030.0WATER BASED42251.8031.0WATER BASED43721.8024.0WATER BASED44371.8425.0WATER BASED44381.7417.0WATER BASED44851.7822.0WATER BASED44851.8226.0WATER BASED45251.7923.0WATER BASED45251.7824.0WATER BASED45911.7821.0WATER BASED46411.7920.0WATER BASED47301.0817.0WATER BASED47321.7920.0WATER BASED49591.8518.0WATER BASED50311.8519.0WATER BASED51471.9121.0WATER BASED51941.9221.0WATER BASED52801.9224.0WATER BASED53371.9229.0WATER BASED54601.9825.0WATER BASED