33/9-4
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General information
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Wellbore history
GeneralWell 33/9-4 was drilled on the Statfjord structure on Tampen Spur in the northern North Sea. The primary objective was to test the northern extension of the Statfjord discovery in the Brent Group.Operations and resultsAppraisal well 33/9-4 was spudded with the semi-submersible installation Norskald on 30 July 1975 and drilled to TD at 3076 m in the Triassic Hegre Group. No significant problem was encountered in the operations. The well was drilled with seawater and spud mud down to 488 m and with Lignosulphonate mud from 488 m to TD.The objective Brent Group was encountered at 2554.5 meters, 33.9 meters high to prognosis. Measured core porosities in the Brent Group averaged 26 percent. Horizontal liquid permeability ranged from 0.05 to 1100.5 milliDarcy and averaged 2155 milliDarcy. The Brent Group was oil filled down to the oil-water contact at 2611.5 m. This is 2 m deeper than on the southern part of Statfjord Field and constitute an in-well gross oil column of 57 m of which 37 m was calculated as net reservoir with 25.4% average porosity and 24.2% average water saturation. Apart from shows in the oil bearing section an oil show was described on a sidewall core at 2618 m.Continuous coring was carried out from within the overlying Middle Jurassic shales through the base of the oil/water contact in the Brent sands, from 2547.2 to 2612.5 meters. Of the 56.7 meters cut by nine cores, 50.7 meters (89 percent) was recovered. No fluid sample was taken on wire line.The well was permanently abandoned on 17 September as an oil appraisal well.TestingTwo drill stem tests were conducted.DST 1 tested the interval 2608 to 2610 m, just above the oil-water contact. This test produced 123 Sm3 oil with 1% bottom sediments and water /day through a 14/64" choke. The GOR was 115.6 Sm3/Sm3, the oil gravity was 38.0 °API, and the gas gravity was 0.682 (air = 1). The bottom hole temperature in this test was 98.9 °C.DST 2 tested the interval 2555 to 2560 m. This test produced 187 Sm3 oil with no bottom sediments and water /day through a 16/32" choke. The GOR was 151 Sm3/Sm3, the oil gravity was 38.3 °API, and the gas gravity was 0.684 (air = 1). The bottom hole temperature in this test was 98.3 °C. On maximum choke (48/64"), DST 2 produced 1164 Sm3 oil /day. -
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]240.003074.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom12547.22555.4[m ]22555.42564.9[m ]32564.92568.6[m ]42568.62577.7[m ]52577.72581.1[m ]62581.12585.0[m ]72585.02594.2[m ]82594.22603.3[m ]92603.32612.4[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]65.2Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
Core photos
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Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit16916671850252625412554273628892974 -
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]pdf1.38PDF11.18 -
Drill stem tests (DST)
Drill stem tests (DST) Test numberFrom depth MD
[m]To depth MD
[m]Choke size
[mm]1.0260826105.62.02555256019.0Drill stem tests (DST) Test numberFinal shut-in pressure
[MPa]Final flow pressure
[MPa]Bottom hole pressure
[MPa]Downhole temperature
[°C]1.02.0Drill stem tests (DST) Test numberOil
[Sm3/day]Gas
[Sm3/day]Oil density
[g/cm3]Gas grav. rel.airGOR
[m3/m3]1.01230.8306492.011640.840886 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CBL6002526CBL16403089CCL1842608DLL MSFL16943074FDC CNL16953074HDT16943074ISF SON2293074 -
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 typeCONDUCTOR30230.036230.00.00SURF.COND.20477.026488.00.00INTERM.13 3/81694.017 1/21703.00.00INTERM.9 5/83044.012 1/43076.00.00 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured2331.34Waterbased5121.50Waterbased6341.14Waterbased17531.76Waterbased