25/1-4
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General information
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Wellbore history
GeneralExploration well 25/1-4 was located on a lower Eocene structure straddling the 25/1 and 30/10 blocks limit, north-east of the main Frigg Field. It was drilled to explore additional gas reserves in the Frigg area. A "Bright spot" phenomenon interpreted as a gas/oil or water table is clearly visible on all the seismic sections crossing the structure. Possible Danian and Maastrichtian reservoirs were considered secondary objectives.Operations and resultsáWell 25/1-4 was spudded with the semi-submersible installation Deepsea Driller on 1 April 1974 and drilled to TD at 2795 m in Maastrichtian marls.The top of the Eocene reservoir (Frigg Formation) at 1967.8 was detected by C1 traces (maximum 3%). Based on shows on cores and electrical logs gas/oil and oil/water contacts were found at 2005.6 m and 2009 m, respectively. The contacts were not the same as on the Frigg Field, implying that this discovery was not in communication with the main Frigg Field. Background gas was weak to nil below 2010 and cuttings or sidewall cores below this depth showed no direct fluorescence or cut. Paleocene was penetrated at 2058 m with well-developed sand bodies as is usual in the area. Hence, the Paleocene contained 190 m net sands of which 25 m consisted of calcareous sandstone and 90 m of shaly sands. All Paleocene sands were water wet. In the Maastrichtian chalk some gas shows were recorded on the section 2757 m to 2763 m. Some hydrocarbon saturation was inferred by logs, but an FIT at 2760 m recovered 2.750 l of mud with only oil traces after a 25 minutes flow period.Coring started at 1922 m, 45.8 m above the Eocene sands. Eight conventional cores were cut from this point down to 2028 m. Two wire line tests were conducted in the oil-bearing zone at 2006.5 m and 2007.5 m. The latter recovered 5.15 l of oil and 4.75 l of mud filtrate.The well was permanently abandoned on 30 May 1974 as an oil and gas discovery.TestingOne drill stem test was carried out through the 7" liner in the Eocene gas zone (perforations at 1991.20 m to 1995.8 m, 1983.20 m to 1987.2, and 1969.7 m to 1974.3 m). Gas flow was stabilized around 610000 m3/day on 3/4" choke (with 5.04 Sm3 associated condensate/day) and 831400 m3/day on a 1" choke (5.04 Sm3 associated condensate/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]450.002795.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom11922.01933.0[m ]21935.51949.5[m ]31953.51970.5[m ]41970.51976.5[m ]51984.01990.0[m ]61993.01999.0[m ]72001.02010.0[m ]82010.02023.5[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]82.5Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
Palynological slides at the Norwegian Offshore Directorate
Palynological slides at the Norwegian Offshore Directorate Sample depthDepth unitSample typeLaboratory1780.0[m]DC1800.0[m]DC1820.0[m]DC1840.0[m]DC1860.0[m]DC1880.0[m]DC1900.0[m]DC1921.0[m]DC1925.0[m]CIGS1941.0[m]CIGS1954.0[m]CIGS1970.0[m]CIGS1976.0[m]CIGS2035.0[m]DC2055.0[m]DC2067.0[m]SWC2075.0[m]DC2095.0[m]DC2115.0[m]DC2119.0[m]SWC2135.0[m]DC2155.0[m]DC2175.0[m]DC2176.0[m]SWC2195.0[m]DC2215.0[m]DC2235.0[m]DC2247.0[m]SWC2255.0[m]DC2275.0[m]DC2300.0[m]DC2320.0[m]DC2340.0[m]DC2360.0[m]DC2371.0[m]SWC2380.0[m]DC2400.0[m]DC2420.0[m]DC2440.0[m]DC2445.0[m]DC2450.0[m]DC2455.0[m]DC2460.0[m]DC2465.0[m]DC2480.0[m]DC2482.0[m]SWC2500.0[m]DC2512.0[m]SWC2520.0[m]DC2532.0[m]SWC2540.0[m]DC2557.0[m]SWC2557.0[m]SWC2565.0[m]DC2603.0[m]SWC2630.0[m]SWC2673.5[m]SWC2745.0[m]SWC2789.0[m]SWC2793.0[m]SWC -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit13395219682058205823162561264326872687 -
Composite logs
Composite logs Document nameDocument formatDocument size [MB]pdf0.32 -
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]PDF0.76PDF8.36PDF0.35PDF5.39pdf3.22PDF11.32PDF5.75PDF0.96PDF0.62PDF1.87PDF0.42PDF11.21PDF3.56 -
Drill stem tests (DST)
Drill stem tests (DST) Test numberFrom depth MD
[m]To depth MD
[m]Choke size
[mm]1.01969199519.0Drill stem tests (DST) Test numberFinal shut-in pressure
[MPa]Final flow pressure
[MPa]Bottom hole pressure
[MPa]Downhole temperature
[°C]1.0Drill stem tests (DST) Test numberOil
[Sm3/day]Gas
[Sm3/day]Oil density
[g/cm3]Gas grav. rel.airGOR
[m3/m3]1.05610000 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CBL12501907CBL17582051CCL PERF19691974CCL PERF19831987CCL PERF19911995DLL19072786FDC CNL19072078FDC CNT19072770GR132420GR SL4201919GR SL19072077GR SL19072792HDT19072791IES4251920IES19072078IES19072770MLL ML19072770SWC20672793SWC20672793 -
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 typeCONDUCTOR30164.036166.00.00LOTINTERM.13 3/8424.017 1/2425.00.00LOTINTERM.9 5/81907.012 1/41910.00.00LOTLINER72795.08 1/22795.00.00LOT -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured9201.3060.012.0water based18401.3875.012.0water based19301.2547.012.0water based20281.2548.014.0water based25631.2546.010.0water based -
Pressure plots
Pressure plots The pore pressure data is sourced from well logs if no other source is specified. In some wells where pore pressure logs do not exist, information from Drill stem tests and kicks have been used. The data has been reported to the NPD, and further processed and quality controlled by IHS Markit.Pressure plots Document nameDocument formatDocument size [MB]pdf0.22