25/2-8
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General information
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Wellbore history
GeneralThe appraisal well 25/2-8 was drilled on the East Frigg Field. The main objectives of the well were to obtain a better estimation of the gas reserves on East Frigg and good pressure data in both the Frigg sand and the Paleocene sand. To achieve better knowledge about the petrophysical characteristics of the different reservoirs, it was decided to core the Frigg sand, the shaly member, the tuff zone and the Paleocene sand.Operations and resultsThe well was spudded with the drill ship Le Pelerin on 18 June 1984 and drilled to TD at 2380 m in the Lower Paleocene Lista Formation. Problems due to tight hole occurred in the 12 1/4" hole section. The pipe got stuck at 1397 m, but was worked free. Problems pressure testing the BOP occurred with hole depth at 1745 m. A cement plug was set from 1000 m to 890 m due to the BOP problems. The core barrel was lost in the hole when pulling out of the hole with core no 9. The fish was recovered. The well was drilled using a water-based mud.The Frigg sand was reached as prognosed at 1917.5 m. This formation is 283 m thick with a 48.5 m hydrocarbon bearing column: gas from 1917.5 m to 1957 m and oil from 1957 to 1966 m. Below this level was 18 m of residual oil. Shows were detected on cores and cuttings down to 2040 m. Balder formation (Paleocene) was reached at 2201 m with several Intra Balder Formation Sandstones. RFT pressure measurements in the Frigg sand and Intra Balder Formation Sandstone indicated that there is no direct fluid communication between the two formations. RFT segregated fluid samples were recovered from 2259 m in Intra Balder Formation Sandstone and at 1956.7 m and 1993 m in the Frigg Formation. The Intra Balder Formation Sandstone sample and the deeper Frigg sample recovered only water and mud filtrate and no gas, while the upper Frigg Sample recovered mud filtrate with traces of oil and about one litre of gas. Nine cores were cut, seven in the Eocene and two in the Paleocene sequence. The well was permanently abandoned as an oil and gas appraisal on 1 August 1984.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]200.002380.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom11919.51926.0[m ]21925.01931.8[m ]31933.61939.0[m ]41975.01982.0[m ]52076.02084.1[m ]62186.02193.5[m ]72193.82200.0[m ]82200.02209.0[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]56.5Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
Core photos
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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 typeCONDUCTOR30180.536181.01.03LOTSURF.COND.13 3/81050.017 1/21065.01.43LOTOPEN HOLE2380.012 1/42380.00.00LOT -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]BGT1801064CBL VDL CCL1251050CST19552268HDT GR10502380LDL CAL GR1801064LDL CNL CAL GR00LDL CNL CAL GR10502380MSFL DLL CAL GR18902260RFT HP GR19222290RFT HP GR19242016RFT HP GR19401965SLS DIL SFL SP GR10502380SLS ISF CAL GR16902040SLS ISF SP GR1801064 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit1184254519511015112519182201220122022206222222292232224222572271227822942306 -
Composite logs
Composite logs Document nameDocument formatDocument size [MB]pdf0.40 -
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]PDF0.68pdf1.13 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured9051.0920.016.0WATER BASED25.06.198410001.0920.016.0WATER BASED25.06.198410651.1020.016.0WATER BASED27.06.198412041.1141.022.0WATER BASED03.07.198412721.1641.022.0WATER BASED03.07.198413901.1731.022.0WATER BASED04.07.198414421.2029.024.0WATER BASED05.07.198416031.2329.020.0WATER BASED06.07.198417451.2528.018.0WATER BASED06.07.198417451.2538.028.0WATER BASED10.07.198417451.2533.09.3WATER BASED12.07.198419191.2732.09.8WATER BASED13.07.198419241.2831.07.8WATER BASED17.07.198419271.2829.07.9WATER BASED16.07.198419431.2830.07.9WATER BASED16.07.198420161.2831.07.8WATER BASED17.07.198420201.2829.07.9WATER BASED16.07.198420751.2826.06.8WATER BASED18.07.198421531.2828.06.8WATER BASED19.07.198421881.2828.08.0WATER BASED20.07.198422011.2831.07.8WATER BASED24.07.198422701.2830.08.8WATER BASED24.07.198423281.2830.07.8WATER BASED24.07.198423601.3032.09.8WATER BASED24.07.198423801.3030.09.8WATER BASED25.07.1984