2/7-31
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General information
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Wellbore history
GeneralThe objectives of drilling the 2/7-31 Ebba Prospect well were to test the hydrocarbon potential of the Permian Rotliegend and Jurassic Lower Ula sandstones in a fault closed structural trap. The prospect was located 10 km west of the Embla field and 1 km west of the Phillips 2/7-19 well, which tested hydrocarbons in the Jurassic Lower Ula Formation. Further, the well should establish proven economic reserves and obtain open hole wire line logs, cores and production tests in both formations.Operations and resultsWell 2/7-31 was spudded with the jack-up rig "Mærsk Galant" on 13 January 1999 and drilling was completed on 5 May 1999 at 4968 m in the Permian Rotliegend Group. It was drilled with spud mud down to 593 m and with oil based Versaport mud from 593 to TD.
Hydrocarbons were encountered first in the Lower Cretaceous Tuxen Formation (Top 4372.1 m), then in the sandstones of the Jurassic Lower Ula (Top 4483.6 m) and Bryne (Top 4634.2 m) Formations, and finally in the sandstone of the Permian Rotliegend Group (Top 4750m). All zones were evaluated either by MWD/LWD log or open and cased hole wire line data. Wire line formation pressure tests were taken throughout the Rotliegend section and oil samples were recovered from two FMT tests at 4793 m and 4812 m. Planned coring of the Jurassic sandstones was cancelled due to operational difficulties in the HPHT environment encountered in this well. Coring in the Rotliegend faced a similar fate but the setting of a liner stabilized the well and one core was taken from the interval 4795.7 - 4798.2 m and three in the interval 4811.3 - 4850.9 m. The well was suspended as an oil discovery.TestingA DST was performed over the Ula Sandstone interval 4565.9 - 4623.8 m. The well flowed at an average stabilized rate of 283 Sm3 oil and 120000 Sm3 gas on a 16/64" choke. -
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]466.004968.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom115734.015741.6[ft ]215785.015877.6[ft ]315877.615905.6[ft ]415908.015915.3[ft ]Cores at the Norwegian Offshore Directorate Total core sample length [m]41.3Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
Core photos
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Oil samples at the Norwegian Offshore Directorate
Oil samples at the Norwegian Offshore Directorate Test typeBottle numberTop depth
MD [m]Bottom depth
MD [m]Fluid typeTest timeSamples availableDSTDST10.000.0023.05.1999 - 23:00YES -
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 typeCONDUCTOR30222.536225.00.00LOTSURF.COND.20584.326586.00.00LOTINTERM.13 3/81946.817 1/21950.01.67LOTINTERM.9 7/84253.812 1/44255.01.95LOTLINER7 3/44968.08 1/24968.02.15LOT -
Drill stem tests (DST)
Drill stem tests (DST) Test numberFrom depth MD
[m]To depth MD
[m]Choke size
[mm]1.0462345656.3Drill stem tests (DST) Test numberFinal shut-in pressure
[MPa]Final flow pressure
[MPa]Bottom hole pressure
[MPa]Downhole temperature
[°C]1.0163Drill stem tests (DST) Test numberOil
[Sm3/day]Gas
[Sm3/day]Oil density
[g/cm3]Gas grav. rel.airGOR
[m3/m3]1.02821203600.702426 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CBIL HDIP GR47634849FMT31574198FMT47834937HDIL MAC ZDL GR19434230HDIL XMAC CN GR47634965HDIL XMAC GR47634849ISF LSS GR157770MRIL47744854MWD CDR ADN DIR42584968SBT19934229SWC47784954VSP1524846ZDL CN GR47634967ZDL CN XMAC GR47634849 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit1211541300030003018307231153146314632033580407440874204420442844372437944374437443944694469463446684750 -
Composite logs
Composite logs Document nameDocument formatDocument size [MB]pdf0.80 -
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].pdf319.61 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured1341.0312.0BENTONITE2271.2615.0BENTONITE2531.146.0BENTONITE5841.138.0BENTONITE6491.4329.0VERSAPORT10061.4323.0VERSAPORT15741.4321.0VERSAPORT17981.5625.0VERSAPORT19471.6722.0VERSAPORT19511.5624.0VERSAPORT20521.6724.0VERSAPORT23501.6725.0VERSAPORT29341.7024.0VERSAPORT31861.6720.0VERSAPORT32071.6722.0VERSAPORT35371.6722.0VERSAPORT38271.6724.0VERSAPORT38951.6725.0VERSAPORT39001.6725.0VERSAPORT39952.1690.0VERSAPORT40202.1691.0VERSAPORT40451.6728.0VERSAPORT41651.7129.0VERSAPORT41672.1246.0VERSAPORT42251.8034.0VERSAPORT42331.8038.0VERSAPORT42431.8232.0VERSAPORT42451.8033.0VERSAPORT42511.8027.0VERSAPORT42591.8032.0VERSAPORT43692.1682.0VERSAPORT43722.0038.0VERSAPORT43822.1246.0VERSAPORT44072.1242.0VERSAPORT44492.1244.0VERSAPORT44772.1243.0VERSAPORT45102.1247.0VERSAPORT45392.1445.0VERSAPORT45422.1649.0VERSAPORT45462.1649.0VERSAPORT45992.1648.0VERSAPORT46712.1650.0VERSAPORT46862.1649.0VERSAPORT47052.0649.0VERSAPORT47222.1451.0VERSAPORT47552.1650.0VERSAPORT47562.1652.0VERSAPORT47592.1657.0VERSAPORT47642.1651.0VERSAPORT47752.0643.0VERSAPORT47812.0642.0VERSAPORT47952.1047.0VERSAPORT47982.0641.0VERSAPORT48112.0645.0VERSAPORT48392.0648.0VERSAPORT48482.0648.0VERSAPORT48512.0649.0VERSAPORT49252.0652.0VERSAPORT49681.70BRINE49682.1681.0VERSAPORT -
Palynological slides at the Norwegian Offshore Directorate
Palynological slides at the Norwegian Offshore Directorate Sample depthDepth unitSample typeLaboratory14560.0[m]DCPETROS14920.0[m]DCPETROS15330.0[m]DCPETROSTA