29/3-1
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General information
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Wellbore history
GeneralWell 29/3-1 was drilled in an area adjacent to several major hydrocarbon discoveries close to the UK-Norway median line. The structure is located in the highest part of a westerly tilted fault panel and the closure is provided by fault to the North East and South and by structural dips westward.The objectives of the well were to test hydrocarbon potential of the Middle Jurassic Brent sandstones; and to test the reservoir potential of the Dunlin sands.Operations and resultsWildcat well 29/3-1 was spudded 20 may 1986 by Dolphin Services A/S semi-submersible installation Byford Dolphin and completed 15 September 1986 at a depth of 4427 m in the Early Jurassic Statfjord Formation. The 17 1/2" hole (756 m to 2252 m) was drilled with KCL/polymer fluid. Well section below 13 3/8" casing point (2252 m) was drilled oil based with Safemul Invert Emulsion mud (80 % base oil). Drilling was delayed due to a destroyed guide block, after that drilling proceeded without significant problems. The Tarbert Formation was water bearing with residual hydrocarbons and minor amounts of gas in the top section. The lower Ness Formation contained a 150 m hydrocarbon column. The Dunlin Group was water bearing. The Statfjord Formation was found tight and water bearing. Two cores were cut in the Brent sandstones in the interval 3525 m to 3561 m. Five RFT samples were taken in the Brent Group: 3821.5 m (Ness: oil and water), 3719 m (Ness: oil and gas), 3697.8 m (Ness: oil and gas), 3556.4 m (Tarbert: water and filtrate), and 3530 m (Tarbert: gas and water). All samples showed unusually high oil filtrate recovery due to a very deep invasion by the oil base mud.The well was plugged and abandoned as a gas and oil discovery.TestingFour drillstem tests were performed in the Brent Group.DST 1B was performed in three zones in the Ness Formation over the interval 3802 m to 3822 m. In this test no flow of reservoir fluid reached surface in 22 hours however, oil (specific gravity: 0.88 g/cm3) and gas (specific gravity (air=l): 0.69) was recovered during reverse circulation.DST 2B was performed in three zones in the Ness Formation over the interval 3682 m to 3725 m. In this test oil rates varied from 665 Sm3 to 433 Sm3 pr day, gas rates varied between 395000 Sm3 to 535000 Sm3 pr day. GOR varied correspondingly between 595 Sm3/Sm3 to 1235 Sm3/Sm3, indicating gas coning from a gas-cap, with the presence of the gas-oil contact near the well. Oil density was 0.87 g/cm3 and gas gravity was 0.68 (air = 1).DST 2C was performed in two zones in the Ness Formation over the interval 3682 m to 3699 m. The test flowed 238.5 Sm3 oil and 438960 Sm3 gas pr day with a GOR of 1840 Sm3/Sm3. Oil density was 0.85 and gas gravity was 0.72.DST 3 was performed in the interval 3522 m to 3530 m in the Tarbert Formation. It produced only Formation water with a little gas. -
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]210.004426.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom13525.03542.9[m ]23543.23560.0[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]34.7Cores 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 typeLaboratory1450.0[m]DCGEOCH1480.0[m]DCGEOCH1510.0[m]DCGEOCH1540.0[m]DCGEOCH1570.0[m]DCGEOCH1600.0[m]DCGEOCH1630.0[m]DCGEOCH1660.0[m]DCGEOCH1690.0[m]DCGEOCH1720.0[m]DCGEOCH1750.0[m]DCGEOCH1780.0[m]DCGEOCH1810.0[m]DCGEOCH1840.0[m]DCGEOCH1870.0[m]DCGEOCH1900.0[m]DCGEOCH1930.0[m]DCGEOCH1960.0[m]DCGEOCH1990.0[m]DCGEOCH2020.0[m]DCGEOCH2050.0[m]DCGEOCH2080.0[m]DCGEOCH -
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 availableDSTDST1B3822.003802.0024.08.1986 - 00:00YESDSTDST2B3725.003682.0002.09.1986 - 00:00YESDSTDST2C3699.003682.0005.09.1986 - 00:00YES -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit15653059015001580159817261726177117802033206120612267328634353440346234623466346635233523356238523862391239124046414742154389 -
Composite logs
Composite logs Document nameDocument formatDocument size [MB]pdf0.48 -
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]pdf18.13 -
Drill stem tests (DST)
Drill stem tests (DST) Test numberFrom depth MD
[m]To depth MD
[m]Choke size
[mm]1.0380238227.92.03682372512.72.13682369912.73.03522353012.7Drill stem tests (DST) Test numberFinal shut-in pressure
[MPa]Final flow pressure
[MPa]Bottom hole pressure
[MPa]Downhole temperature
[°C]1.036.0001302.054.00030.00050.0001242.154.00021.00037.0001293.048.0001.00034.000119Drill stem tests (DST) Test numberOil
[Sm3/day]Gas
[Sm3/day]Oil density
[g/cm3]Gas grav. rel.airGOR
[m3/m3]1.020.8780.6902.04405340000.8680.68012122.12364380000.8450.72018583.0 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]BGL GR7562250CBL VDL GR12462248CBL VDL GR19003468CORR DST-234953615CORR DST-333903475CST34754385DELTA-T34683847DIPMETER34704428DIS BHC GR156758DIS BHC GR756900DIS BHC GR7562250DIS BHC GR22513485DIS BHC GR34683613DIS GR22513427DITE SDTA GR44323550ENERJET-2200220EPL PCD34684433JB BRIDGE PLUG32003450JB BRIDGR PLUG34403450JB PACKER DST-2C36453708JB PLUG DST-237163747JB PLUG DST-335483599LDL CNL GR22513487LDL CNL GR34684433MWD2084427NGS44333468RFT GR35263543RFT HP35303861RFT HP35303697RFT HP35533821RFT HP35563610RFT HP37194050VSP8002240VSP21004430 -
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 typeCONDUCTOR30204.036208.01.13LOTSURF.COND.20756.026770.01.49LOTINTERM.13 3/82252.017 1/22265.01.87LOTINTERM.9 5/83468.012 1/43484.02.06LOTLINER74427.08 1/24427.00.00LOT -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured2041.0510.020.0WATER BASED23.05.19862041.0510.0WATER BASED20.05.19862081.0510.020.0WATER BASED21.05.19862951.1217.026.0WATER BASED23.05.19867601.1317.026.0WATER BASED23.05.19867701.1317.026.0WATER BASED23.05.19867701.1515.010.0WATER BASED08.06.19867701.1517.010.8WATER BASED08.06.19867701.1517.011.3WATER BASED10.06.19867701.0510.010.0WATER BASED11.06.19867701.1017.07.0WATER BASED15.06.19867701.1517.011.3WATER BASED09.06.19869311.1016.06.7WATER BASED15.06.198614711.1418.010.5WATER BASED15.06.198615831.1418.010.5WATER BASED15.06.198617821.2022.011.0WATER BASED16.06.198619441.2020.010.5WATER BASED17.06.198620351.2219.09.6WATER BASED18.06.198621691.2126.011.5WATER BASED19.06.198622521.3021.09.0WATER BASED29.06.198622521.3021.09.0WATER BASED26.06.198622651.2317.08.0WATER BASED22.06.198622651.3021.09.0WATER BASED24.06.198622651.2026.012.4WATER BASED22.06.198622651.2519.09.0WATER BASED23.06.198622651.302.19.0WATER BASED25.06.198622801.3021.09.0WATER BASED29.06.198625001.3517.06.5OIL BASED29.06.198627951.3517.013.0OIL BASED30.06.198631821.4721.07.0OIL BASED01.07.198633291.5019.08.0OIL BASED02.07.198633951.5021.07.5OIL BASED03.07.198634261.5020.07.0OIL BASED06.07.198634271.5824.09.1OIL BASED04.08.198634681.5020.09.0OIL BASED09.07.198634681.5020.09.5OIL BASED10.07.198634741.5022.09.0OIL BASED06.07.198634841.5021.08.5OIL BASED06.07.198634841.5020.010.0OIL BASED08.07.198634841.5020.010.0OIL BASED07.07.198635071.5020.09.5OIL BASED14.07.198635221.6014.013.0OIL BASED09.09.198635221.6014.013.0OIL BASED11.09.198635251.5119.09.0OIL BASED14.07.198635431.5119.09.0OIL BASED14.07.198635611.4616.09.0OIL BASED14.07.198636001.596.027.0OIL BASED09.09.198636001.6014.013.0OIL BASED09.09.198636131.4620.07.0OIL BASED15.07.198636131.4618.08.0OIL BASED16.07.198636721.4619.08.0OIL BASED17.07.198636851.5517.07.7OIL BASED21.07.198637151.5517.07.7OIL BASED21.07.198637281.5618.08.6OIL BASED21.07.198637501.5932.08.0OIL BASED26.08.198637941.5619.09.0OIL BASED21.07.198638831.5618.07.7OIL BASED22.07.198639001.5922.08.0OIL BASED11.08.198639161.5922.08.0OIL BASED11.08.198639161.5922.08.0OIL BASED12.08.198639171.5922.08.0OIL BASED11.08.198639281.5618.08.6OIL BASED23.07.198639281.5619.08.6OIL BASED24.07.198639991.5624.010.5OIL BASED28.07.198640541.5624.09.1OIL BASED28.07.198641721.5624.09.1OIL BASED28.07.198642981.5824.010.5OIL BASED30.07.198643841.5824.09.6OIL BASED30.07.198643851.5824.09.6OIL BASED31.07.198643851.5824.09.6OIL BASED01.08.198644271.5824.09.1OIL BASED04.08.198644271.5824.09.1OIL BASED05.08.198644271.5824.08.1OIL BASED04.08.198644271.5922.07.6OIL BASED06.08.198644271.5922.07.6OIL BASED07.08.198644271.5922.07.6OIL BASED08.08.1986 -
Thin sections at the Norwegian Offshore Directorate
Thin sections at the Norwegian Offshore Directorate DepthUnit3546.25[m ]3535.80[m ]3536.00[m ]3532.60[m ]3525.40[m ]3527.60[m ] -
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]pdf0.22