34/7-14
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General information
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Wellbore history
GeneralWell 34/7-14 was drilled in on the "B-structure", today named the Tordis Field, in the southern part of block 34/7. The Middle Jurassic Brent Group reservoir is located in tilted fault blocks dipping in a westerly direction within the southern fault segment about 1.4 km south of the well 34/7-12. The structure has a NE-SW trend and is bounded to the east and north by major faults, i.e. Northern Main Fault and Southern Main Fault with throws of 50-200 m. The primary purpose of well 34/7-14 was to further delineate and appraise the Tordis Field. The main target of the well was the sandstones in the Brent Group. Secondary objective was the sandstones of the Early Jurassic Cook Formation.Operations and resultsAppraisal well 34/7-14 was spudded with the semi-submersible installation "Vildkat Explorer" on 28 September 1989 and drilled to a total depth of 2653 m in the Early Jurassic Burton Formation. Shallow seismic indicated gas at 246 & 285 m, 344 m, 376 m, and 511 m. Measurement and logging while-drilling (MWD) verified the indication at 511 m as a thin, gas-filled sand. The upper part of the well was drilled as a 9 1/2" pilot hole without a riser and was plugged back from 511 m due to lack of reliable gas readings in the sand layer. Lost circulation occurred at 2137 m, and the well was plugged back to the 13 3/8" casing shoe. The well was drilled with gel mud (barite, bentonite, caustic soda, soda ash) down to 495 m and with KCl mud from 495 m to TD.Down to 2189 m, the top of the Brent reservoir, the well proved mainly claystones. Exceptions to this were the sandy Utsira Formation of Miocene/Pliocene age encountered at 856 m, and sandstones within the Hordaland Group encountered in the interval 1167 - 1456 m. The Jurassic comprised the Middle Jurassic Viking and Brent Groups and the Early Jurassic Dunlin Group.& Top Brent Group was encountered at 2189 m.& The Brent Group sandstones proved oil bearing. Exact determination of an OWC was not established due to pressure depletion effects, but oil down to (ODT) 2247 m was proven by logs.Eleven conventional cores were attempted. Nine were recovered in the interval 2194 m - 2408 m (Tarbert and Ness Formation), two in the interval 1950 m - 1959.5 m were unsuccessful, and one was recovered in the interval 1610 m - 1619 m (Hordaland Group). Two FMT segregated samples were taken on wire line at 2223 m (base Tarbert Formation: gas, oil, and water) and one at sample point 2247 (Ness Formation: gas, oil, water, mud). Three runs were made with core gun. One hundred and fifty sidewall cores were attempted, 72 were recovered. The well was permanently abandoned as an oil appraisal on 2 December 1989.TestingTwo DST tests were carried out in the oil zone. Test no 1 (Ness Formation, 2232.3 m - 2241.3 m) produced fluid at a rate of 960 Sm3/d during the main flow period, with a GOR of 80 Sm3/Sm3. Test no 2 (Tarbert Formation, 2204.7 m - 2210,7 m) produced fluid at a rate of 1150 Sm3/d during main flow, with a GOR of 67 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]500.002652.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom11610.91614.221617.21618.731959.01959.542194.02222.0[m ]52222.02249.2[m ]62249.52275.7[m ]72276.52300.0[m ]82300.02325.5[m ]92325.52353.5[m ]102353.52380.2[m ]112380.52408.2[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]212.7Cores 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 availableDSTDST12207.302216.30OIL19.11.1989 - 10:00YESDSTDST22179.702185.70OIL25.11.1989 - 05:30YES -
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 typeCONDUCTOR30234.036238.00.00LOTINTERM.20491.026495.01.49LOTINTERM.13 3/81559.017 1/21610.01.79LOTINTERM.9 5/81988.012 1/42010.01.80LOTLINER72653.08 1/22653.00.00LOT -
Drill stem tests (DST)
Drill stem tests (DST) Test numberFrom depth MD
[m]To depth MD
[m]Choke size
[mm]1.02232224112.72.02204221014.3Drill stem tests (DST) Test numberFinal shut-in pressure
[MPa]Final flow pressure
[MPa]Bottom hole pressure
[MPa]Downhole temperature
[°C]1.015.40032.500842.015.70033.00083Drill stem tests (DST) Test numberOil
[Sm3/day]Gas
[Sm3/day]Oil density
[g/cm3]Gas grav. rel.airGOR
[m3/m3]1.09600.7162.011200.712 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]AC WAVETRAIN19822650CBL VDL GR15551985CBL VDL GR19882651CDL CN GR19822650CDL CN SL21562377COREGUN00COREGUN00DIFL ACL CDL GR4901572DIFL ACL CDL GR15552002DIFL ACL GR19822650DIPLOG19822650DIPLOG GR15551999DLL MLL GR21352377FMT21912365MWD - GR RES DIR1732651VSP5002600 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit1739629961267131413501412145616531653170518361836200721732173217821822182218921892227230523432413241325432629 -
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]pdf18.67 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured3061.20WATER BASED29.09.19893551.20WATER BASED03.10.19893551.20WATER BASED03.10.19893551.20WATER BASED03.10.19894911.2013.015.0WATER BASED30.11.19894911.2013.04.0WATER BASED04.12.19895231.1014.012.0WATER BASED10.10.19895301.20WATER BASED05.10.19895301.05WATER BASED09.10.19895301.05WATER BASED06.10.198912011.1820.011.0WATER BASED10.10.198915751.3016.012.0WATER BASED11.10.198915751.3018.09.0WATER BASED16.10.198916101.4018.012.0WATER BASED16.10.198917511.4017.012.0WATER BASED16.10.198919501.6327.010.0WATER BASED16.10.198919591.6326.011.0WATER BASED18.10.198920101.6831.010.0WATER BASED31.10.198920101.6026.014.0WATER BASED27.10.198920321.6830.013.0WATER BASED31.10.198920651.6226.012.0WATER BASED19.10.198921251.6832.015.0WATER BASED31.10.198921891.6829.010.0WATER BASED02.11.198921891.6830.015.0WATER BASED02.11.198921911.6527.014.0WATER BASED14.11.198921911.6526.013.0WATER BASED15.11.198921911.6527.010.0WATER BASED16.11.198921911.6526.011.0WATER BASED17.11.198921911.6523.013.0WATER BASED20.11.198921911.6524.013.0WATER BASED20.11.198921911.6524.013.0WATER BASED20.11.198921911.6528.024.0WATER BASED21.11.198921911.6525.014.0WATER BASED23.11.198921911.6523.014.0WATER BASED24.11.198921911.6523.014.0WATER BASED27.11.198921911.6524.013.0WATER BASED27.11.198921911.6520.012.0WATER BASED28.11.198921911.6522.011.0WATER BASED29.11.198921911.6523.014.0WATER BASED27.11.198921911.6522.014.0WATER BASED27.11.198923801.6833.012.0WATER BASED08.11.198923801.6833.010.0WATER BASED08.11.198923811.6836.018.0WATER BASED08.11.198924081.6827.011.0WATER BASED08.11.198924901.6528.015.0WATER BASED08.11.198926201.6527.016.0WATER BASED09.11.198926531.6832.012.0WATER BASED10.11.198926531.6524.012.0WATER BASED13.11.198926531.6525.012.0WATER BASED13.11.198926531.6527.010.0WATER BASED13.11.1989 -
Palynological slides at the Norwegian Offshore Directorate
Palynological slides at the Norwegian Offshore Directorate Sample depthDepth unitSample typeLaboratory990.0[m]DCSAGA1010.0[m]DCSAGA1020.0[m]DCSAGA1040.0[m]DCSAGA1050.0[m]DCSAGA1070.0[m]DCSAGA1080.0[m]DCSAGA1100.0[m]DCSAGA1110.0[m]DCSAGA1130.0[m]DCSAGA1140.0[m]DCSAGA1160.0[m]DCSAGA1170.0[m]DCSAGA1190.0[m]DCSAGA1200.0[m]DCSAGA1220.0[m]DCSAGA1230.0[m]DCSAGA1250.0[m]DCSAGA1260.0[m]DCSAGA1280.0[m]DCSAGA1290.0[m]DCSAGA1310.0[m]DCSAGA1320.0[m]DCSAGA1340.0[m]DCSAGA1350.0[m]DCSAGA1370.0[m]DCSAGA1380.0[m]DCSAGA1400.0[m]DCSAGA1410.0[m]DCSAGA1430.0[m]DCSAGA1440.0[m]DCSAGA1460.0[m]DCSAGA1490.0[m]DCSAGA1500.0[m]DCSAGA1520.0[m]DCSAGA1530.0[m]DCSAGA1550.0[m]DCSAGA1560.0[m]DCSAGA1580.0[m]DCSAGA1590.0[m]DCSAGA1600.0[m]DCSAGA1608.0[m]SWCSAGA1630.0[m]DCSAGA1641.0[m]SWCSAGA1662.0[m]SWCSAGA1674.0[m]SWCSAGA1692.0[m]SWCSAGA1697.0[m]SWCSAGA1720.0[m]DCSAGA1732.0[m]SWCSAGA1750.0[m]DCSAGA1760.0[m]DCSAGA1790.0[m]DCSAGA1800.0[m]DCSAGA1822.0[m]SWCSAGA1830.0[m]DCSAGA1850.0[m]DCSAGA1861.0[m]SWCSAGA1865.0[m]DCSAGA1871.0[m]SWCSAGA1880.0[m]DCSAGA1895.0[m]DCSAGA1903.0[m]SWCSAGA1915.0[m]DCSAGA1920.0[m]DCSAGA1935.0[m]DCSAGA1952.0[m]SWCSAGA1965.0[m]DCSAGA1980.0[m]DCSAGA1985.0[m]DCSAGA1995.0[m]DCSAGA2010.0[m]DCSAGA2025.0[m]DCSAGA2036.0[m]SWCSAGA2055.0[m]DCSAGA2070.0[m]DCSAGA2083.0[m]SWCSAGA2100.0[m]DCSAGA2115.0[m]DCSAGA2127.0[m]SWCSAGA2130.0[m]DCSAGA2133.0[m]DCSAGA2145.0[m]DCSAGA2161.0[m]DCSAGA2180.0[m]SWCSAGA2186.0[m]SWCSAGA2189.0[m]SWCSAGA2194.0[m]CSAGA2213.5[m]CSAGA2229.0[m]CSAGA2233.0[m]CSAGA2251.0[m]CSAGA2257.5[m]CSAGA2265.0[m]CSAGA2269.0[m]CSAGA2277.5[m]CSAGA2289.0[m]CSAGA2289.6[m]CSAGA2308.5[m]CSAGA2325.5[m]CSAGA2346.0[m]CSAGA2360.0[m]CSAGA2380.5[m]CSAGA2395.0[m]CSAGA2408.0[m]CSAGA2410.0[m]SWCSAGA2424.0[m]DCSAGA2436.0[m]DCSAGA2451.0[m]DCSAGA2466.0[m]DCSAGA2481.0[m]DCSAGA2496.0[m]DCSAGA2511.0[m]DCSAGA2526.0[m]DCSAGA2541.0[m]DCSAGA2556.0[m]DCSAGA2580.0[m]SWCSAGA2586.0[m]DCSAGA2601.0[m]DCSAGA2616.0[m]DCSAGA2631.0[m]DCSAGA2652.0[m]DCSAGA