7120/1-2
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General information
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Wellbore history
GeneralBlock 7120/1 is situated on the southern margin of the Loppa High and is bisected by the east-west trending Southern Loppa High boundary fault, which separates the Loppa High from the Hammerfest Basin to the south. The main objective of well 7120/1-2 was two seismostratigraphically defined wedges (of inferred Aptian age) in a large fault-bound closure against the Loppa High. Additional objectives were provided by a lower wedge of inferred Hauterivian age and Early Jurassic/Late Triassic elastics truncated beneath the Base Cretaceous unconformity, both down dip from the structural culmination.Operations and resultsThe well spudded with the semi-submersible installation Ross Rig on 1 January 1989 and drilled to a total depth of 2630 m in Late Triassic sediments of the Fruholmen Formation. No shallow gas was encountered at any depth. The rig had to be moved three times due to problems with boulders that increased the hole inclination too much. Rough weather conditions, with waves exceeding 16 m, delayed drilling with several days. The well was drilled with seawater and spud mud down to 617 m and with KCl /Polymer mud from 617 m to TD.Well 7120/1-2 penetrated two seismically defined "wedges" which contained three distinct clastic packages. The uppermost wedge (Wedge I from1585 m to1826 m) was dated as Early to Middle Albian in age, whilst the lower hydrocarbon-bearing wedge contains two units of latest Ryazanian / Early Valanginian (Wedge IIa from1878 m to 1984 m) and Early Volgian age (Wedge IIb from1984 m to 2138 m) respectively. These units had not previously been penetrated on the Barents Shelf.Oil shows (direct fluorescence) was recorded on cuttings and cores in several intervals below 1931 m. Based on DST, logs, cores and RFT pressure measurements it was concluded that an oil column in excess of 90 m was encountered in Wedge IIa. Hydrocarbon saturations were considered reliable and although averaging only 50 %, could be as high as 65 % in both the upper and lower reservoir intervals (corresponding to Production Tests 3A and 3B respectively). Reservoir properties in the hydrocarbon-bearing interval were in general very poor and the intercalation of thin sand-shale beds made it impossible to pick an oil-water contact with any confidence. All other interpreted hydrocarbons, with the exception of an isolated sand in the Hekkingen Formation, were considered to be immovable. A segregated RFT sample was recovered from 1888.5 m (within the Production Test 3A interval in the Lower Cretaceous reservoirs of Wedge IIa). Both sample chambers were opened on the rig and found to contain oil, water and gas. A total of 0.0012 m3 of 31 deg API (0.871 g/cm3) oil was recovered along with 0.074 m3 of gas. A second RFT sample was recovered from 2153.5 m (a two to five meter thick isolated sand in the Upper Jurassic Hekkingen Formation). The lower sampling chamber from this interval was opened on the rig; it contained 0.0023 m3 of 41°API (0.820 g/cm3) oil and 0.3706 m3 of gas. Attempts to recover RFT samples and pressures from the interval 2506 m to 2543 m failed due to tight Formation. Four conventional cores were cut. In addition, a 10 cm core was recovered from the junk basket tool run to retrieve lost bullets prior to drilling ahead at the 7" liner depth. Core 1 was cut from 1815 m to 1825 m in Wedge I, core 2 was cut from 1957 m to 1969 m in Wedge IIa, core 3 (from junk basket: black fissile claystone with strong smell of H2S) was retrieved from 2147 m in the Hekkingen Formation, core 4 was cut from 2581 m to 2583 m, and the fifth core was cut from 2583 m to 2585.5 m. Cores 4 and 5 were cut in the Fruholmen Formation, and both jammed of.The well was permanently abandoned on 28 March 1989 as an oil discoveryTestingTwo hydrocarbon production tests were planned for well 7120/1-2. The planned test intervals were 2506 m to 2543 m (Production Test #1 in the Fruholmen Formation) and 1879 m to 1896 m / 1944 m to1971 m (Production Test 2A / Test 2B in Wedge IIa). During Production Test 2, the tubing conveyed perforating guns parted from the bottom hole assembly and perforated the water-bearing sands below the proposed test interval. This incident led to a repeat of the test over the interval 1879 m to1971 m as Production Test 3. Test 1 gave no flow, but bottom hole samples and bottoms up contained minute traces of oil. Test 2 produced water, while the final, oil zone test in Wedge IIa (Test 3A and Test 3B) proved moveable oil. However the oil came very slowly with alternating gas and slugs of emulsified oil, and only after displacement of the original diesel cushion with Nitrogen. -
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]630.002630.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom11815.01825.0[m ]21957.01968.0[m ]32581.02582.0[m ]42582.02585.5[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]25.5Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
Core photos
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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 availableDSTTEST3A1879.001971.0021.03.1989 - 10:30YESDST1888.001896.0021.03.1989 - 00:00YESDSTDST3B1944.001971.0022.03.1989 - 00:00YES -
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 typeCONDUCTOR30401.0360.00.00LOTINTERM.20607.026622.01.37LOTINTERM.9 5/81544.012 1/21564.01.27LOTLINER72144.08 1/22151.01.34LOTLINER4 1/22630.05 7/82630.00.00LOT -
Drill stem tests (DST)
Drill stem tests (DST) Test numberFrom depth MD
[m]To depth MD
[m]Choke size
[mm]2.01879197112.7Drill stem tests (DST) Test numberFinal shut-in pressure
[MPa]Final flow pressure
[MPa]Bottom hole pressure
[MPa]Downhole temperature
[°C]2.0Drill stem tests (DST) Test numberOil
[Sm3/day]Gas
[Sm3/day]Oil density
[g/cm3]Gas grav. rel.airGOR
[m3/m3]2.01500.673 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CBL VDL11641546CBL VDL14402145CHKSHT4152135CST414604CST6231537CST6431537CST15602136CST19722145CST21642622CST24602578DIL BHC402616DIL BHC6101550DIL BHC15462144DIL BHC21452561DIL BHC24772628DIL MSFL21452630DLL MSFL15462137LDL CNL AMS6101552LDL CNL CAL402615LDL CNL NGS15462144LDL CNL NGS24502629LDL CNL NGT21442564MWD3422140RFT21532541RFT25082578SHDT21452630SHDT CAL15452141VSP7002584 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit32840840815601560158515851586159118261878198419862138215822112211236524522506 -
Composite logs
Composite logs Document nameDocument formatDocument size [MB]pdf0.47 -
Geochemical information
Geochemical information Document nameDocument formatDocument size [MB]pdf3.20 -
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]pdf42.89 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured3661.04WATER BASED04.01.19896731.0215.020.0WATER BASED16.01.19898271.2019.024.0WATER BASED16.01.19898801.2019.024.0WATER BASED16.01.198911001.0217.020.0WATER BASED17.01.198912901.2017.019.0WATER BASED17.01.198915001.2020.028.0WATER BASED19.01.198915001.2020.028.0WATER BASED20.01.198915001.2020.028.0WATER BASED25.01.198915001.2022.034.0WATER BASED19.01.198916001.2021.028.0WATER BASED25.01.198916701.2021.020.0WATER BASED26.01.198917401.2026.021.0WATER BASED26.01.198917811.2024.021.0WATER BASED27.01.198917811.2024.021.0WATER BASED30.01.198918301.1820.021.0WATER BASED30.01.198918501.20WATER BASED20.03.198918501.20WATER BASED22.03.198918501.20WATER BASED28.03.198918501.20WATER BASED16.03.198918871.2022.023.0WATER BASED31.01.198919341.2021.023.0WATER BASED01.02.198919501.2022.020.0WATER BASED03.02.198919501.2022.020.0WATER BASED02.02.198919901.02WATER BASED22.03.198920401.1822.022.0WATER BASED06.02.198920501.03WATER BASED13.03.198920501.03WATER BASED14.03.198920501.03WATER BASED15.03.198921011.1822.022.0WATER BASED06.02.198921401.1820.023.0WATER BASED08.02.198921401.1820.023.0WATER BASED09.02.198921401.1820.023.0WATER BASED13.02.198921591.2020.021.0WATER BASED17.02.198921601.2020.021.0WATER BASED20.02.198922581.2021.023.0WATER BASED20.02.198923841.2021.023.0WATER BASED20.02.198923841.2021.023.0WATER BASED21.02.198924561.2021.022.0WATER BASED22.02.198924941.2021.022.0WATER BASED24.02.198925501.2021.022.0WATER BASED27.02.198925641.2021.022.0WATER BASED28.02.198925811.2021.022.0WATER BASED28.02.198925851.2021.022.0WATER BASED02.03.198925851.2021.022.0WATER BASED28.02.198926001.03WATER BASED10.03.198926001.03WATER BASED07.03.198926001.03WATER BASED09.03.198926001.03WATER BASED13.03.198926301.03WATER BASED07.03.198926301.2021.020.0WATER BASED03.03.198926301.2021.020.0WATER BASED06.03.1989 -
Palynological slides at the Norwegian Offshore Directorate
Palynological slides at the Norwegian Offshore Directorate Sample depthDepth unitSample typeLaboratory413.3[m]SWC469.3[m]SWC531.3[m]SWC595.3[m]SWC643.0[m]SWC680.0[m]SWC800.0[m]SWC870.0[m]SWC980.0[m]SWC1020.0[m]SWC1065.0[m]SWC1145.0[m]SWC1160.0[m]SWC1420.0[m]SWC1460.0[m]SWC1500.0[m]SWC1558.0[m]DC1559.5[m]SWCRRI1563.5[m]SWCRRI1566.1[m]SWC1576.0[m]DC1584.9[m]SWCRRI1589.5[m]SWC1593.5[m]SWCRRI1594.0[m]DC1601.1[m]SWC1621.0[m]DC1625.1[m]SWC1643.0[m]DC1651.1[m]SWC1658.0[m]SWCRRI1677.0[m]SWC1682.0[m]DC1688.0[m]DCRRI1703.0[m]DCRRI1718.0[m]DCRRI1724.0[m]DC1748.0[m]DCRRI1754.0[m]DC1778.0[m]DCRRI1784.1[m]SWC1799.0[m]DC1808.0[m]DCRRI1808.0[m]SWC1811.0[m]DC1816.4[m]C1817.0[m]CRRI1817.4[m]C1817.5[m]CRRI1818.4[m]C1819.3[m]CFUGRO1819.4[m]CRRI1820.0[m]CRRI1820.1[m]CRRI1820.1[m]C1820.4[m]C1822.4[m]C1822.6[m]C1822.6[m]CFUGRO1830.5[m]SWCRRI1835.0[m]DC1838.0[m]SWCRRI1838.0[m]SWC1844.0[m]DC1853.0[m]DC1856.5[m]SWCRRI1862.0[m]DC1863.1[m]SWC1863.1[m]SWCRRI1868.0[m]SWCRRI1871.0[m]DC1880.0[m]DC1883.5[m]SWC1883.5[m]DCRRI1889.0[m]DC1898.0[m]SWCRRI1901.0[m]DC1904.0[m]DCRRI1905.1[m]SWC1910.0[m]DC1913.0[m]DCRRI1919.0[m]DC1922.0[m]DCRRI1928.0[m]DCRRI1928.5[m]SWC1931.0[m]DC1937.0[m]DCRRI1940.0[m]DC1943.0[m]DCRRI1946.0[m]DCRRI1949.0[m]DC1953.6[m]SWC1955.0[m]DC1957.0[m]C1957.0[m]CRRI1957.7[m]CFUGRO1958.3[m]C1959.2[m]CRRI1959.2[m]CICHRON1959.2[m]CFUGRO1959.4[m]CICHRON1960.0[m]CICHRON1960.1[m]CICHRON1960.9[m]CRRI1960.9[m]CICHRON1961.2[m]CICHRON1961.5[m]CICHRON1962.4[m]CICHRON1963.0[m]CICHRON1963.5[m]CICHRON1963.9[m]CICHRON1964.1[m]CRRI1964.2[m]CICHRON1964.5[m]C1964.6[m]DC1964.9[m]CICHRON1965.2[m]CRRI1965.2[m]C1965.5[m]CICHRON1965.9[m]CICHRON1966.0[m]CFUGRO1966.1[m]CICHRON1966.4[m]CICHRON1966.5[m]C1966.8[m]CFUGRO1966.8[m]CICHRON1967.3[m]CICHRON1967.3[m]C1967.5[m]C1967.8[m]CRRI1967.8[m]CICHRON1971.5[m]SWCRRI1971.5[m]SWC1973.0[m]DC1975.2[m]SWC1977.5[m]SWC1980.0[m]SWCRRI1980.0[m]SWC1981.5[m]SWCRRI1981.5[m]SWC1982.0[m]DC1988.0[m]DCRRI1991.0[m]DC1992.3[m]SWC2000.0[m]DCRRI2000.0[m]DC2009.0[m]DC2009.0[m]DCRRI2016.6[m]SWC2018.0[m]DCRRI2018.0[m]DC2030.0[m]DC2030.0[m]DCRRI2042.0[m]DC2048.0[m]DCRRI2051.0[m]DC2060.0[m]DC2063.0[m]SWC2067.1[m]SWCRRI2067.1[m]SWC2069.0[m]DC2078.0[m]DCRRI2081.0[m]DC2090.0[m]DC2097.1[m]SWC2099.0[m]DC2108.0[m]DCRRI2110.1[m]SWC2111.0[m]DCRRI2111.0[m]DC2114.0[m]DCRRI2120.0[m]DC2129.0[m]DC2130.5[m]SWC2132.0[m]DCRRI2135.0[m]DCRRI2136.4[m]SWC2138.0[m]DCRRI2141.0[m]DCRRI2141.0[m]DC2147.0[m]DC2147.0[m]DCRRI2150.0[m]CSTATOIL2150.0[m]DC2150.0[m]CRRI2150.0[m]C2156.0[m]SWC2156.0[m]SWCRRI2160.0[m]SWCRRI2165.0[m]DC2170.0[m]SWC2170.0[m]SWCRRI2180.0[m]SWCRRI2180.0[m]SWC2189.0[m]DC2195.0[m]SWC2198.0[m]DC2198.0[m]DCRRI2207.0[m]DCRRI2210.0[m]SWC2213.0[m]DC2219.0[m]DC2219.0[m]DCRRI2228.0[m]DCRRI2234.0[m]DC2243.0[m]DCRRI2244.0[m]SWC2246.0[m]DC2249.0[m]DCRRI2249.0[m]DC2258.0[m]DCRRI2270.0[m]DC2285.0[m]DC2285.0[m]DCRRI2357.0[m]DC2368.5[m]SWC2372.0[m]DC2384.0[m]DC2390.0[m]SWC2415.0[m]SWC2425.0[m]SWC2432.0[m]DC2448.0[m]SWC2450.0[m]DC2460.0[m]SWC2469.0[m]SWC2474.0[m]DC2507.0[m]DC2509.5[m]SWC2526.5[m]SWC2531.0[m]DC2555.0[m]DC2561.0[m]SWC2573.0[m]DC2582.6[m]C2584.5[m]C2585.4[m]C2597.0[m]DC2612.5[m]SWC2626.0[m]SWC -
Thin sections at the Norwegian Offshore Directorate
Thin sections at the Norwegian Offshore Directorate DepthUnit1816.15[m ]1817.32[m ]1961.72[m ]1962.73[m ]2581.80[m ]2583.48[m ]