34/8-7
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General information
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Wellbore history
GeneralWell 34/8-7 is located on the western flank of the Tampen Spur and is situated approximately 7.4 kilometres due east of well 34/8-4S, in the Visund prospect. This was the third exploration well to be drilled in the licence area. The primary objective of well 34/8-7 was to test the Jurassic Brent Group and Statfjord Formation in the hanging wall of the Visund Fault. The secondary objectives were to establish a good seismic to well correlation and to fulfil licence obligations.Operations and resultsExploration well 34/8-7 was spudded with the semi-submersible rig "Polar Pioneer" on 21 March 1992 and drilled to TD at 5460 m in the Triassic Hegre Group. The well was drilled with spud mud down to 1444 m and with KCl/PHPA/Polymer mud from 1444 m to 3288 m. From 3288 m the mud system was gradually changed to a HTHP (high temperature stable polymers) mud. Still, towards TD of the well it was evident that some of the chemical/polymers was decomposing and forming carbonates.Conglomeratic density flow deposits (Intra Draupne Formation sandstone) were found in the upper part of the Draupne Formation. From a gross thickness of 134.5m, 5.75m of net sand were identified of which 5.25m were regarded as net pay. An average porosity value 9.4% and average Sw of 50.1% were computed for the pay section. A core cut in the Intra Draupne sandstone gave 5.2 % core porosity on average.The primary objective Brent Group was encountered at 4632.5 m. The entire Brent Group was interpreted as being gas bearing. From a gross thickness of 134.5m, 36.5m of net sand were recognised with 36.5m of net pay. An average porosity of 9.8% and average Sw of 30.4% were determined. A core cut in the Brent Group, gave an average porosity of 9.9 %. The sandy member of Cook Formation was found to be gas bearing, but poor reservoir properties reduced the net pay to only 2.0 m with an average porosity of 8.3 % and average Sw of 36.1 %.No net pay was identified in the Amundsen sand.The Statfjord Formation came in at 5118 m. It was 88.5 m thick of which 22.5 m was net sand and 18.75 m was identified as net gas bearing pay. Cores cut in the Statfjord Formation gave an average core porosity of 7.1 % porosity.A total of five cores were cut in isolated intervals throughout the well. Core number 1 was cut in the Intra Draupne Sandstone, core number 2 was cut in the Tarbert and Ness Formations, cores number 3 and 4 were cut in the Statfjord Formation, while core number 5 was cut in the Hegre Group. Attempts to take RFT pre-test in the Draupne equivalent conglomerate proved to be unsuccessful due to the tight nature of the Formation. Because of hole washouts and high down hole temperature and pressure anomalies, no RFT pressure measurements could be obtained in the Brent Group and Statfjord Formations.After running the liner as part of preparing for drill stem testing, "Polar Pioneer" had to be released for other purposes. The well was therefore suspended on 16 July 1992 with the provision that testing of the reservoir zones would be performed at a later date. The well was re-entered (34/8-7 R) with the semi-submersible installation "Polar Pioneer" on 19 November 1992 for testing. It was permanently abandoned as a gas discovery on 10 February 1993.TestingWell 34/8-7 R was tested in two intervals. In Test 1 in the Statfjord Formation (5117.8 m ? 5210.0 m) no production was achieved. Test 2 in the Brent Group (4671.7 m ? 4731.0 m) produced gas.< -
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]1450.005460.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom14471.04491.4[m ]24654.04656.8[m ]35118.05118.3[m ]45127.05132.3[m ]55422.05429.9[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]36.6Cores 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 typeLaboratory2694.0[m]SWCHYDRO3470.5[m]SWCHYDRO3484.0[m]SWCHYDRO3492.5[m]SWCHYDRO3506.0[m]SWCHYDRO3538.0[m]SWCHYDRO3549.5[m]SWCHYDRO3565.5[m]SWCHYDRO3580.0[m]SWCHYDRO3597.0[m]SWCHYDRO3608.0[m]SWCHYDRO3625.0[m]SWCHYDRO3646.0[m]SWCHYDRO3660.0[m]SWCHYDRO3670.0[m]SWCHYDRO3685.0[m]SWCHYDRO3709.0[m]SWCHYDRO3740.0[m]SWCHYDRO3754.5[m]SWCHYDRO3763.0[m]SWCHYDRO3777.0[m]SWCHYDRO3794.0[m]SWCHYDRO3800.0[m]SWCHYDRO3841.5[m]SWCHYDRO3855.0[m]SWCHYDRO3986.0[m]SWCHYDRO4013.0[m]SWCHYDRO4043.0[m]SWCHYDRO4155.0[m]SWCHYDRO4207.0[m]SWCHYDRO4227.0[m]SWCHYDRO4261.0[m]SWCHYDRO4278.0[m]SWCHYDRO4322.0[m]SWCHYDRO4337.0[m]SWCHYDRO4352.0[m]SWCHYDRO4379.0[m]SWCHYDRO4396.0[m]SWCHYDRO4402.0[m]SWCHYDRO4457.0[m]SWCHYDRO4471.5[m]CHYDRO4474.3[m]CHYDRO4476.0[m]COD4476.5[m]CHYDRO4478.0[m]CHYDRO4478.0[m]COD4479.0[m]CHYDRO4481.5[m]CHYDRO4482.5[m]CHYDRO4485.1[m]CHYDRO4486.0[m]COD4487.6[m]CHYDRO4490.0[m]CHYDRO4490.0[m]COD4522.5[m]SWCHYDRO4574.0[m]SWCHYDRO4645.8[m]CHYDRO4649.8[m]CHYDRO4652.0[m]COD4652.1[m]CHYDRO4654.0[m]COD4656.0[m]COD4656.8[m]COD4850.0[m]DCOD4900.0[m]DCOD4950.0[m]DCOD5000.0[m]DCOD5050.0[m]DCOD5100.0[m]DCOD5118.2[m]CHYDRO5127.7[m]CHYDRO5132.2[m]COD5132.2[m]CHYDRO5150.0[m]DCOD5200.0[m]DCOD5231.0[m]DCOD -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit35810711095116014061413163016541875187519282022203720812081232032603826403440344298437444664466458445954633463346554699471447644767476748084953497050865106511852085208 -
Composite logs
Composite logs Document nameDocument formatDocument size [MB]pdf0.71 -
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]pdf17.95 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CST GR34703855CST GR39864866DIL LSS GR SP AMS48135236DIL LSS LDL CNL NGT SP AMS32103855DIL LSS LDL CNL NGT SP AMS39494900DIL LSS SP GR AMS14363285DLL GR AMS43004898DLL MSFL CAL GR AMS51685467DLL MSFL GR AMS48105224FMS-4 CAL GR AMS52505463FMS-4 GR47835232FMS-4 GR AMS39494900LDL CNL CAL GR AMS51665438LDL CNL NGT AMS48235225MSFL GR AMS43004893MSFL GR AMS43004893MWD - GR RES DIR3684769RFT GR AMS43984828RFT GR AMS44664840RFT GR AMS46995141VSP33005220 -
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 typeCONDUCTOR30444.536446.00.00LOTINTERM.18 5/81436.0261438.01.65LOTINTERM.13 3/83264.017 1/23270.01.89LOTINTERM.9 5/83945.012 1/43947.02.00LOTLINER75460.08 1/25460.00.00LOT -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured4451.2011.0WATER BASED5061.0827.0WATER BASED10651.0825.0WATER BASED14411.0826.0WATER BASED17501.3923.0WATER BASED21511.3927.0WATER BASED23491.3926.0WATER BASED24831.3925.0WATER BASED25531.3926.0WATER BASED25561.3925.0WATER BASED26641.3926.0WATER BASED27661.3927.0WATER BASED27921.3927.0WATER BASED28001.3927.0WATER BASED28881.3927.0WATER BASED29551.3927.0WATER BASED30091.4026.0WATER BASED30601.3927.0WATER BASED31331.3927.0WATER BASED31531.3927.0WATER BASED32611.3925.0WATER BASED32881.3928.0WATER BASED33321.3925.0WATER BASED33761.3925.0WATER BASED34531.3917.0WATER BASED35331.3919.0WATER BASED35621.3922.0WATER BASED36361.3919.0WATER BASED37121.3918.0WATER BASED37241.3918.0WATER BASED37631.3918.0WATER BASED38391.3921.0WATER BASED39231.3920.0WATER BASED39611.3916.0WATER BASED39611.3921.0WATER BASED40061.3918.0WATER BASED41801.3921.0WATER BASED43371.5025.0WATER BASED44461.5022.0WATER BASED44711.6225.0WATER BASED44741.6226.0WATER BASED44921.6226.0WATER BASED45181.6524.0WATER BASED45681.7022.0WATER BASED45801.7628.0WATER BASED45891.7625.0WATER BASED46051.8222.0WATER BASED46481.8223.0WATER BASED46571.8223.0WATER BASED47251.8218.0WATER BASED47661.8225.0WATER BASED49001.8215.0WATER BASED49471.8216.0WATER BASED49611.8217.0WATER BASED50051.8219.0WATER BASED50411.8224.0WATER BASED50921.8226.0WATER BASED51121.8220.0WATER BASED51271.8222.0WATER BASED51331.8228.0WATER BASED51691.8227.0WATER BASED52271.8225.0WATER BASED52311.8228.0WATER BASED52501.8228.0WATER BASED53021.8230.0WATER BASED53191.8228.0WATER BASED53701.8226.0WATER BASED54031.8227.0WATER BASED54221.8226.0WATER BASED54311.8222.0WATER BASED54601.8220.0WATER BASED -
Thin sections at the Norwegian Offshore Directorate
Thin sections at the Norwegian Offshore Directorate DepthUnit4471.13[m ]4479.50[m ]4483.73[m ]4486.46[m ]4489.06[m ]4489.36[m ]4648.40[m ]4653.27[m ]4655.90[m ]5130.96[m ]5422.54[m ]5423.86[m ]5427.53[m ]5129.60[m ]5118.20[m ]4825.30[m ]4817.20[m ]