7121/7-1
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General information
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Wellbore history
GeneralWell 7121/7-1 was drilled in order to test the Lower/Middle Jurassic sandstone on the eastern part of the Albatross structure on Tromsøflaket. The primary target was defined as sandstone intervals in Early-Middle Jurassic and Late Triassic.Operations and resultsWildcat well 7121/7-1 was spudded with the semi-submersible installation West Vanguard on 11 June 1984 and drilled to TD at 2160 m in the Late Triassic Fruholmen Formation. No significant problems were encountered during drilling. The well was drilled with spud mud down to 764 m and with a gypsum/polymer mud from 764 m to TD.Logs, RFT pressure gradients, and cores indicated gas in the Lower/Middle Jurassic sandstone (Stø Formation) encountered at a depth of 1849 m. Gas/water contact was evaluated to 1902.5 m RKB, the same as found in well 7120/9-1, also drilled on the Albatross structure. From the GWC down to TD in the well shows were observed in sandstones on cores and cuttings. Four cores were cut in the interval 1851 m to 1935 m in the Stø Formation. Two segregated samples were taken, at 1900.2 m and at 1851.0 m. The 2-3/4 gallon chamber from 1900.2 m was bled off offshore and gave an opening pressure at 2220 psig. The sample contained 58.25 cuft of gas and 1 litre of liquid consisting of 800 cc water/mud filtrate and 200 cc condensate. The 2 3/4 gallon chamber from 1850.5 m contained 2200 psig with 4500 cc water based liquid, a small volume condensate, and 41 cuft of gas.The well was permanently abandoned on 5 August 1984 as a gas appraisal well.TestingTwo DST were performed, one water test over the interval 1947.2 m to 1960.18 m and one gas test over the interval 1867 m to 1872 m. The recorded temperatures were in agreement with those observed in well 7120/9-1. The reservoir fluids had the same composition in well 7121/7-1 as in well 7120/9-1. The sandstone in the tested water zone had good reservoir properties. The gas test flowed on average 501000 Sm3 gas/day during the main flow, with a separator gas/oil ratio of 18000 Sm3/Sm3. -
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]420.002157.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom11851.01867.1[m ]21868.01894.4[m ]31895.01922.8[m ]41922.81935.0[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]82.5Cores 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 typeLaboratory1401.0[m]DCOD1410.0[m]DCOD1419.0[m]DCOD1428.0[m]DCOD1440.0[m]DCOD1452.0[m]DCOD1461.0[m]DCOD1473.0[m]DCOD1479.0[m]DCOD1491.0[m]DCOD1500.0[m]DCOD1509.0[m]DCOD1521.0[m]DCOD1530.0[m]DCOD1542.0[m]DCOD1551.0[m]DCOD1824.0[m]DCRRI1833.0[m]DCRRI1839.0[m]DCRRI1845.0[m]DCRRI1851.2[m]CRRI1853.9[m]CRRI1855.6[m]CRRI1858.6[m]CRRI1861.3[m]CRRI1864.8[m]CRRI1867.0[m]CRRI1870.0[m]CRRI1872.8[m]CRRI1876.9[m]CRRI1880.2[m]CRRI1883.8[m]CRRI1886.3[m]CRRI1890.7[m]CRRI1894.4[m]CRRI1896.6[m]CRRI1898.5[m]CRRI1899.8[m]CRRI1902.9[m]CRRI1905.6[m]CRRI1907.7[m]CRRI1910.7[m]CRRI1914.6[m]CRRI1915.7[m]CRRI1918.5[m]CRRI1921.3[m]CRRI1924.4[m]CRRI1926.5[m]CRRI1929.2[m]CRRI1932.6[m]CRRI1935.0[m]CRRI1938.0[m]DCRRI1944.0[m]DCRRI1950.0[m]DCRRI1956.0[m]DCRRI1962.0[m]DCRRI1968.0[m]DCRRI1974.0[m]DCRRI1980.0[m]DCRRI -
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 availableDSTDST21866.001871.0023.07.1984 - 00:00YES -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit351442442894894931931158817321793184818491849190820012045 -
Composite logs
Composite logs Document nameDocument formatDocument size [MB]pdf0.33 -
Geochemical information
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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]pdf13.65pdf1.15 -
Drill stem tests (DST)
Drill stem tests (DST) Test numberFrom depth MD
[m]To depth MD
[m]Choke size
[mm]1.01950196067.52.01866187124.4Drill stem tests (DST) Test numberFinal shut-in pressure
[MPa]Final flow pressure
[MPa]Bottom hole pressure
[MPa]Downhole temperature
[°C]1.021.00020.000362.021.00010.00018.00061Drill stem tests (DST) Test numberOil
[Sm3/day]Gas
[Sm3/day]Oil density
[g/cm3]Gas grav. rel.airGOR
[m3/m3]1.02.02850100018000 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CBL VDL5201495CBL VDL CCL13001975CET GR CCL13001975CST8001498CST15402142DLL MSFL GR18252154ISF BHC GR SP CAL3511507ISF BHC GR SP CAL18542157ISF BHC MSFL GR SP CAL15001941LDL CNL NGT15002158LDL GR4151505RFT18501922RFT18512059SHDT GR7522158VELOCITY5402150 -
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 typeCONDUCTOR30415.036419.00.00LOTSURF.COND.20752.026770.01.52LOTINTERM.13 5/81500.017 1/21517.01.53LOTINTERM.9 5/82160.012 1/42160.00.00LOT -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured7061.07WATER BASED7701.20WATER BASED12221.166200.0WATER BASED15171.161800.0WATER BASED15171.162000.0WATER BASED15581.141200.0WATER BASED19221.251600.0WATER BASED21601.241100.0WATER 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]pdf0.28