2/11-3 A
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General information
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Wellbore history
GeneralThe Hod complex was proved to consist of two individual structures by well 2/11-3, which was drilled about 2.5 km due east of 2/11-2. Seismically, the Hod structural complex is difficult to map due to shallow gas in the Tertiary, mainly over the western part of the structure, which complicates the time to depth conversion. As it turned out, the chalk in 2/11-2 was drilled close to the limit of structural closure of the East Structure and was therefore dry with shows only. Well 2/11-3 A was a sidetrack from well 2/11-3 to test Late Cretaceous chalk in a graben feature indicated by seismic in the crestal regional of the East Hod structure. A graben, if present, would have possibilities for preservation of younger Maastrichtian rock which in general is of high reservoir quality with high porosity and often very high oil saturation.Operations and resultsWell 2/11-3A was sidetracked from just below the 13 3/8-inch casing shoe on 3 December 197 7 and drilled to TD at a total measured depth of 3400 m (2857 m TVD) in the Late Cretaceous Hod Formation. The pipe stuck at TD prior to logging and deviation survey. After working on the stuck pipe the string was disconnected at 3189 m and the well was kicked-off on the low side in order to complete logging and testing of the pay-zone discovered before the pipe got stuck. This technical sidetrack was drilled to 3333 m (2812 m TVD).Top Chalk was encountered in the sidetrack at 3189.5 meters (2713 meters TVD). The uppermost 5 m belonged to the Ekofisk Formation. Then followed 58.5 m of Tor Formation, 13 m of tight Middle Hod Formation, and 70 m of Lower Hod. The Chalk was found oil bearing from top Chalk to TD in the sidetrack, with exception of 8 m in Middle Hod. Shows on cuttings were recorded in the primary well bore down to 3370 m. No oil shows were reported from above top Chalk.Seven cores were cut in the top Chalk section in the primary un-logged well bore in the interval from 3192.4 m to 3250.3 m. Recovery varied from 18 % to 100 %. No wire line fluid samples were taken.The well was permanently abandoned on 13 March 1978 as an oil appraisal well.TestingTwo Drill Stem Tests were conducted in the well.DST 1 tested the interval 3268 to 3280 m. After hydraulic fracturing the test flowed on average 88 Sm3 oil and 12700 Sm3 gas /day through a 24/64" choke. The average GOR was 133 Sm3/Sm3, the oil gravity was 29.1 deg API, and the gas gravity was 0.8 (air=1). Maximum temperature recorded down hole was 102 deg C. A final flow on a 32/64" choke gave sluggish flow but did not increase rates much.DST 2 tested the interval 3230 to 3236 m. After acid stimulation the test flowed on average 915 Sm3 oil and 104500 Sm3 gas /day through a 32/64" choke. The average GOR was 114 Sm3/Sm3, the oil gravity was 33.9 deg API and the gas gravity was 0.69 (air = 1). Maximum temperature recorded down hole was 107 deg C. -
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]1298.463162.50 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom13192.03198.3[m ]23201.53206.3[m ]33206.33209.9[m ]43226.03230.1[m ]53231.93235.7[m ]63235.93239.1[m ]73240.93251.4[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]36.3Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
Core photos
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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]pdf1.75 -
Drill stem tests (DST)
Drill stem tests (DST) Test numberFrom depth MD
[m]To depth MD
[m]Choke size
[mm]1.0326832809.52.0323032369.5Drill 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]1.088127430.8800.8002.0519634290.8400.690 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CBL VDL TT8493114CBL VDL TT GR29963298CBL VDL TT GR30003287CNL FDC GR CAL31213335CONT-DIP31263327DLL MSFL GR SP CAL31273334ISF SON SP GR12802055TEMP1502838TEMP31003272 -
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 typeINTERM.9 5/83129.012 1/43130.01.88LOTOPEN HOLE3400.08 1/23400.00.00LOT -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured24461.79waterbased32881.74waterbased