16/5-1
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General information
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Wellbore history
GeneralWell 16/5-1 is located on the Utsira High in the North Sea. The main target of the 16/5-1 well ("Vali") was a pinch-out of Paleocene sands on a seismic monoclinal. The interest in this trap was emphasized by oil-shows in Paleocene sands in surrounding wells.Operations and resultsWildcat well 16/5-1 was spudded with the semi-submersible installation Pentagone 81 on 17 January 1971 and drilled to TD at 1943 m in granitic basement rocks. The well was drilled using seawater-based mud.The Paleocene sands, which were the main objective of the Vali well, were not present. A thin Cretaceous series was found directly overlaying Caledonian basement rocks. From 1923 m to TD the well penetrated migmatitic granite, highly fractured and slightly weathered down to 1940 m. No shows were recorded, only background gas of C1 from1% to 3 % while drilling the tertiary series. The only reservoirs encountered in Vali well were 164 m net sand in the sand-shale sequence in the Utsira Formation from 754 m to 1012 m. These sands, very fine to medium and shelly, have very high porosity, more than 32 %. However, they are not sufficiently buried to form a trap and they were water wet. Two cores were cut: the first from 1573 to 1584 m in the Sele and Lista Formations, 15 m below the cinerites, and the second from 1929 to 1943 m in the basement rocks. No fluid samples were attempted. The well was permanently abandoned as a dry well on 8 February 1971.TestingNo drill stem test was performed -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom11573.01582.0[m ]21929.01942.0[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]22.0Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
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 typeCONDUCTOR30164.036165.00.00LOTINTERM.13 3/8507.017 1/2511.00.00LOTINTERM.9 5/81535.012 1/41538.00.00LOTOPEN HOLE1950.08 1/21950.00.00LOT -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]BHC5071533BHC GR15351938GR1211533HDT5071533HDT15351938IES5071533IES15351938SWC00SWC00TL1251230VEL00 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit127754842101215271527155715801648166216621699175618481859185919231925 -
Composite logs
Composite logs Document nameDocument formatDocument size [MB]pdf0.16 -
Geochemical information
Geochemical information Document nameDocument formatDocument size [MB]pdf0.02pdf94.12 -
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]pdf5.02 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured5070.00seawater15330.00seawater19430.00seawater -
Palynological slides at the Norwegian Offshore Directorate
Palynological slides at the Norwegian Offshore Directorate Sample depthDepth unitSample typeLaboratory765.0[m]DC820.0[m]DC900.0[m]DC930.0[m]DC960.0[m]DC990.0[m]DC1020.0[m]DC1065.0[m]DC1095.0[m]DC1130.0[m]DC1155.0[m]DC1200.0[m]DC1260.0[m]DC1300.0[m]DC1330.0[m]DC1360.0[m]DC1390.0[m]DC1420.0[m]DC1470.0[m]DC1495.0[m]DC1530.0[m]DC1558.0[m]DC1573.0[m]DC1573.0[m]CSAGA1577.0[m]CSAGA1579.0[m]CSAGA1582.0[m]CSAGA1600.0[m]DC1630.0[m]DC1650.0[m]DC1675.0[m]DC1695.0[m]DC1715.0[m]DC1735.0[m]DC1750.0[m]DC1855.0[m]DC1880.0[m]DC1895.0[m]DC1920.0[m]DC