25/3-1
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General information
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Wellbore history
GeneralWell 25/3-1 was designed to drill a narrow NNW-SSE trending horst structure on the Utsira High. The main objective for the well was to test the hydrocarbon potential of the Middle Jurassic Vestland Group sandstones, and the Lower Jurassic Statfjord Formation sandstones. The site survey indicated two high amplitude events at two different levels west (135 m MSL) and northwest (180 m MSL) of the proposed well location that could indicate shallow gas.Operations and resultsWildcat well 25/3-1 was spudded with the semi-submersible installation West Vanguard on 4 July 1989and drilled to TD at 3922 m in Late Triassic sediments of the Statfjord Formation. To assure safe operation in possible shallow gas zones, the interval (198 to 720 m) was drilled as a 17 1/2 " pilot hole before opening to 26" hole. Drilling went on without any serious problems. No shallow gas was encountered.The Vestland Group reservoir was reached 65 m deeper than expected. The reservoir was thinner than expected, and of relatively bad quality and water bearing. The Statfjord Formation was reached 128 m deeper than expected, and also water bearing. Very weak shows were recorded in two samples from 2165 m and 2170 m in the Balder Formation; otherwise no shows were recorded while drilling. Geochemical source rock screening found very good Type II kerogen (oil) source potential in the Draupne Formation and good Type II-III kerogen (gas + light oil) source potential in the Heather shales and the Vestland Group coals and shales. The well has reached early maturity probably at ca 2700 m, so the Draupne shale is in the very early oil window.Two cores were cut. Core no 1 was cut from 3112 to 3130 m in the Vestland Group, and no 2 from 3858 to 3876 m in the Statfjord Formation. The RFT tool was run, but due to obstruction in the hole representative pressure points were not obtained. No fluid sample was taken.The well was permanently abandoned on 5 September 1989 as a dry hole.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]200.003922.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom13112.03129.9[m ]23858.03873.9[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]33.7Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
Core photos
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Palynological slides at the Norwegian Offshore Directorate
Palynological slides at the Norwegian Offshore Directorate Sample depthDepth unitSample typeLaboratory1680.0[m]DCRRI1700.0[m]DCRRI1720.0[m]DCRRI1740.0[m]DCRRI1760.0[m]DCRRI1780.0[m]DCRRI1800.0[m]DCRRI1820.0[m]DCRRI1840.0[m]DCRRI1860.0[m]DCRRI1880.0[m]DCRRI1900.0[m]DCRRI1920.0[m]DCRRI1940.0[m]DCRRI1960.0[m]DCRRI1980.0[m]DCRRI2000.0[m]DCRRI2020.0[m]DCRRI2040.0[m]DCRRI2060.0[m]DCRRI2080.0[m]DCRRI2100.0[m]DCRRI2120.0[m]DCRRI2140.0[m]DCRRI2160.0[m]DCRRI2180.0[m]DCRRI2200.0[m]DCRRI2220.0[m]DCRRI2240.0[m]DCRRI2260.0[m]DCRRI2280.0[m]DCRRI2310.0[m]DCRRI2330.0[m]DCRRI2350.0[m]DCRRI2370.0[m]DCRRI2390.0[m]DCRRI2410.0[m]DCRRI2430.0[m]DCRRI3112.0[m]CRRI3116.0[m]CRRI3119.0[m]CRRI3126.0[m]CRRI3128.0[m]CRRI3325.0[m]DCRRI3340.0[m]DCRRI -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit13610362127215921592253231424142470283630163016304331073107312033343870 -
Composite logs
Composite logs Document nameDocument formatDocument size [MB]pdf0.62 -
Geochemical information
Geochemical information Document nameDocument formatDocument size [MB]pdf2.60 -
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]pdf15.41 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CBL VDL GR17502990CBL VDL GR CCL13601984CDM AP19982970CDM AP29973918CDM AP31003918DIL DDBHC GR AMS SP7031998DIL DDBHC GR AMS SP19842995DIL GR SLS MSFL AMS29933921FMS GR29933922LDL CNL NGS AMS29933922LDL GR AMS7031998LDL GR AMS19842995MSD19982970MWD1993922NGT RATIOS29933922SHDT GR AMS19842993STL GR20032985VELOCITY7073921 -
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 typeCONDUCTOR30197.036198.00.00LOTINTERM.20703.026720.01.33LOTINTERM.13 3/81983.017 1/21998.01.66LOTINTERM.9 5/82991.012 1/43005.01.93LOTOPEN HOLE3922.08 1/23922.00.00LOT -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured9091.0916.09.8WATER BASED14.07.198912431.1319.010.7WATER BASED14.07.198918401.2022.011.7WATER BASED17.07.198918581.2126.012.7WATER BASED18.07.198919481.2023.012.2WATER BASED19.07.198919981.2022.012.2WATER BASED20.07.198930711.2526.07.3WATER BASED10.08.198931181.2531.05.8WATER BASED11.08.198931981.2534.012.7WATER BASED14.08.198932911.2532.012.7WATER BASED14.08.198933531.2530.011.7WATER BASED14.08.198933951.2528.011.7WATER BASED15.08.198934291.3031.011.7WATER BASED22.08.198934561.2630.011.7WATER BASED16.08.198934911.3031.013.7WATER BASED17.08.198935691.3031.012.7WATER BASED22.08.198937191.3533.014.7WATER BASED22.08.198937741.3534.013.7WATER BASED22.08.198938581.3534.011.7WATER BASED24.08.198938581.3534.011.7WATER BASED24.08.198938711.4537.012.7WATER BASED25.08.1989