6507/7-8
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General information
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Wellbore history
GeneralWell 6507/7-8 is a replacement well for well 6507/7-7 and was drilled on the southern flank of the Heidrun Field on the Halten Terrace. The primary objective was to appraise reserves in this part of the field. Further objectives were to obtain a water sample from the Aldra (Tilje) Formation, evaluate vertical communication between sandstone units in the Tomma Formation (Fangst Group), and to obtain oriented cores from this section for fracture orientation studies.Operations and resultsAppraisal well 6507/7-8 was spudded with the semi-submersible installation Treasure Hunter on 9 June 1987 and drilled to TD at 2855 m in Early Jurassic sediments of the Åre Formation. Some problems with low penetration rate and bit balling occurred in the 17 1/2" section in swelling clay, sometimes interbedded with pebbles. The well was drilled with seawater and gel sweeps down to 1035 m and with KCl/polymer mud from 1035 m to TD.The top of the Tertiary was encountered at 604 m. No indications of overpressured shallow gas were seen. The top of the Tomma Formation (Fangst Group) was penetrated at 2436.2 m and consisted of two hydrocarbon bearing sandstone units separated by a ca 2 m thick shaley interval at 2468 m. For the two units as a whole the logs gave an average SW of 19.4% over the 60.6 m reservoir and a net/gross ratio of 0.921. RFT pressure data indicated a common pressure regime across the shale band at 2468 m, with an OWC at 2495 m. Oil shows were first observed on cores at 2435.5 m where a uniform light buff coloured oil stain was observed. It had pale yellow fluorescence and gave a pale yellow fast blooming cut. Below this the cut was predominantly fast and streaming. A dark brown residue was observed after the solvent had evaporated. With depth the residue became medium brown. Below 2464 m the shows became patchy with the cut residue becoming a pale yellowish grey. No shows were observed below the OWC.Seven cores were cut from 2405 m in the Melke Formation, through the Fangst Group, and down to 2525 m in the Ror Formation. The average core recovery was 98%. 30 RFT pressure tests were taken through the reservoir. No fluid samples were taken on wire line.The well was permanently abandoned on 2 August 1987 as an oil and gas appraisal.TestingTwo DST's were conducted in the intervals 2473 m to 2480 m (DST 1) and 2438 m to 2441 m (DST 2). DST 1 flowed 30 deg API oil at 187 Sm3/day and gas at 19900 Sm3/day through a 20/64" choke. The gas gravity was 0.68 (air = 1) and the GOR was 106 Sm3/Sm3. DST 2 flowed 29 API oil at 1105 Sm3/day and gas at 136570 Sm3/day through a 52/64" choke. The gas gravity was 0.7 (air = 1) and the GOR was 124 Sm3/Sm3. The gauge temperatures recorded in the tests were 90.3 and 86.7 deg C in DST 1 and DST 2, respectively.The results of the well test did not indicate vertical communication across the shaley interval at 2468 m. -
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]1035.002855.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom12405.02423.5[m ]22423.52441.7[m ]32442.02458.9[m ]42460.12479.0[m ]52479.02497.3[m ]62497.52516.8[m ]72516.02525.0[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]119.1Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
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 availableDSTDST12473.002480.0019.07.1987 - 00:00YESDSTDST22438.002441.0021.07.1987 - 00:00YES -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit35735714631877187719971997202320822384238424362436246824702497249725582787 -
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]pdf12.90pdf2.95pdf12.42 -
Drill stem tests (DST)
Drill stem tests (DST) Test numberFrom depth MD
[m]To depth MD
[m]Choke size
[mm]1.0247324807.92.02441243820.62.12441243820.62.22441243820.6Drill stem tests (DST) Test numberFinal shut-in pressure
[MPa]Final flow pressure
[MPa]Bottom hole pressure
[MPa]Downhole temperature
[°C]1.08.0002.08.0002.18.0002.28.000Drill stem tests (DST) Test numberOil
[Sm3/day]Gas
[Sm3/day]Oil density
[g/cm3]Gas grav. rel.airGOR
[m3/m3]1.01750.8820.670802.01145990000.8820.670862.111450.8870.700862.211370.8870.70087 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CBL CCL20152530DIL MSFL SDT GR SP23992828DLL LDL CNL NGL CAL GR23992828FMS GR23992835MWD - GR RES DIR4732855RFT GR24392797SDT CBL8002398VSP12002825VSP23602600 -
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 typeCONDUCTOR30468.0361035.01.02LOTSURF.COND.201027.2261054.01.51LOTINTERM.13 3/82398.517 1/22403.01.84LOTINTERM.9 5/82833.512 1/42855.00.00LOT -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured4661.04WATER BASED11.06.19874701.04WATER BASED15.06.19875441.04WATER BASED15.06.198710211.03WATER BASED15.06.198710351.04WATER BASED16.06.198710351.04WATER BASED17.06.198710351.04WATER BASED18.06.198710351.04WATER BASED19.06.198710351.04WATER BASED22.06.198710541.16WATER BASED22.06.198712111.17WATER BASED22.06.198715411.28WATER BASED23.06.198717951.32WATER BASED24.06.198719531.38WATER BASED25.06.198721981.40WATER BASED26.06.198721991.40WATER BASED29.06.198723441.42WATER BASED29.06.198723591.42WATER BASED29.06.198724031.42WATER BASED30.06.198724031.20WATER BASED02.07.198724031.4218.05.8WATER BASED01.07.198724051.2111.019.0WATER BASED03.07.198724291.2117.08.2WATER BASED06.07.198724651.2116.07.2WATER BASED06.07.198725131.2115.07.2WATER BASED06.07.198725251.2114.06.7WATER BASED07.07.198726141.2015.010.1WATER BASED13.07.198726581.2015.07.2WATER BASED13.07.198728551.2013.02.4WATER BASED14.07.198728551.199.05.8WATER BASED20.07.198728551.2016.07.7WATER BASED13.07.198728551.2119.05.3WATER BASED13.07.198728551.1912.02.4WATER BASED15.07.198728551.1912.02.4WATER BASED16.07.198728551.1910.06.2WATER BASED17.07.198728551.198.05.3WATER BASED20.07.198728551.198.05.3WATER BASED21.07.198728551.198.05.3WATER BASED22.07.198728551.198.05.3WATER BASED23.07.198728551.198.05.3WATER BASED24.07.198728551.199.05.7WATER BASED27.07.198728551.199.04.8WATER BASED28.07.198728550.00WATER BASED29.07.198728550.00WATER BASED31.07.198728550.00WATER BASED03.08.1987 -
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]pdf0.27