6407/6-3
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General information
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Wellbore history
GeneralWell 6407/6-3 was drilled on the eastern side of the Halten Terrace, roughly mid-way between the Draugen and Midgard Discoveries off shore mid-Norway. It was drilled on the same structure as well 6407/6-2, which was junked due to a disastrous shallow gas blow-out. The primary objective was to test for hydrocarbon accumulation in sandstones of Middle Jurassic age (Fangst Group). Secondary objectives were possible hydrocarbon accumulations in Early Jurassic sandstone, and to verify the geophysical and structural interpretation and improve the geological, paleontological and geochemical understanding of the area. Total depth was to be in rocks of Triassic age or 4000 m in order to satisfy the licence commitment.Operations and resultsWildcat well 6407/6-3 was spudded with the semi-submersible installation Dyvi Delta on 13 December 1986 and drilled to TD at 3220 m in Late Triassic sediments of the Åre Formation. No significant technical problems were encountered in the operations, which were completed within planned time and budget. No shallow gas was encountered in the well. At 512 m, the interval thought to correspond with that which caused the uncontrolled blow out from well 6407/6-2, a small resistivity peak was recorded, although the gamma ray reading remained constant. A negative drilling break was recorded at the same depth but here was no increase in gas. The well was drilled with spud mud down to 459 m, with gypsum/polymer mud from 459 m to 2470 m, and with gel/lignite/lignosulphonate mud from 2470 m to TD.The Middle Jurassic sandstones were penetrated at 2461 m and were found to be gas/condensate bearing with a thin light oil leg. From FMT pressure gradients, logs and shows on cores an OWC can be set at 2583 m. There were shows and petroleum odour all through the reservoir down to 2583 m. Shows description, RFT pressure measurements, DST results and geochemical analyses indicated a gas/light oil contact at ca 2570 - 2575 m. Below 2583 m there was no fluorescence and only a weak, bluish white streaming cut. Sandstones of the Early Jurassic Tilje and Åre Formations were encountered at 2727 m. These were water wet without shows.Seven cores were cut in the Fangst Group from 2472 to 2615 m. No wire line fluid samples were taken.The well was permanently abandoned on 16 February 1987 as a gas/condensate discoveryTestingThree drill stem tests were performed in the Fangst GroupDST 1 tested the interval 2570 - 2577 m (later corrected to 2574.2 – 2581.2 m). It produced 338600 Sm3 gas, 151.6 Sm3 condensate and 20 - 45 m3 water /day through a 72/64" choke. GOR was 2233 Sm3/Sm3, the oil density was 0.810 g/cm3, the gas gravity was 0.760 (air = 1). The bottom hole temperature measured in the test was 93 deg C.DST 2 tested the interval 2546 - 2555 m (later corrected to 2550.2 – 2559.2 m). It produced 1249000 Sm3 gas, 512.7 Sm3 condensate and 1 m3 water /day through a 96/64" choke. GOR was 2437 Sm3/Sm3, the oil density was 0.737 g/cm3, the gas gravity was 0.723 (air = 1). The bottom hole temperature measured in the test was 98 deg C.DST 3 tested the interval 2479 - 2489 m (later corrected to 2483 – 2493 m). It produced 1298000 Sm3 gas, 517.7 Sm3 condensate /day through a 72/64" choke. No water was produced. GOR was 2507 Sm3/Sm3, the oil density was 0.752 g/cm3, the gas gravity was 0.742 (air = 1). The bottom hole temperature measured in the test was 96 deg C. -
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]470.003220.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom12472.02482.6[m ]22491.02509.4[m ]32509.42521.6[m ]42522.02545.0[m ]52552.02566.2[m ]62575.02584.4[m ]72588.02615.0[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]114.8Cores 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 availableDSTTEST12581.202574.2031.01.1987 - 00:00YESDSTTEST22559.202550.2005.02.1987 - 00:00YESDSTTEST32493.002483.0010.02.1987 - 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 typeCONDUCTOR30324.036332.00.00LOTSURF.COND.20430.026459.01.55LOTINTERM.13 3/81391.017 1/21418.01.95LOTINTERM.9 5/82458.012 1/42470.01.98LOTLINER73083.08 1/23100.01.89LOT -
Drill stem tests (DST)
Drill stem tests (DST) Test numberFrom depth MD
[m]To depth MD
[m]Choke size
[mm]1.02570257712.72.02546255519.13.02479248919.1Drill stem tests (DST) Test numberFinal shut-in pressure
[MPa]Final flow pressure
[MPa]Bottom hole pressure
[MPa]Downhole temperature
[°C]1.02.03.0Drill stem tests (DST) Test numberOil
[Sm3/day]Gas
[Sm3/day]Oil density
[g/cm3]Gas grav. rel.airGOR
[m3/m3]1.01152280000.8180.77019792.02607530000.7520.75528973.03267460000.7410.7202288 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CBL11002303CDL CN GR24553217DIFL ACL GR4303090DIFL BHC ACL GR SON30783217DIPLOG GR24553090DLL MLL GR24553090DTL13002314FMT HP24553018MWD - GR RES DIR4303100SPL24553090SWC470538TL200900VSP4663181 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit251251122714631463191519151978206924142445244524512461246124922548263926392691269827272902 -
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]pdf10.02pdf3.17 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured4591.157200.08.5WATER BASED19.12.19864591.158800.08.5WATER BASED22.12.19864591.158200.08.9WATER BASED22.12.19864621.157200.08.9WATER BASED22.12.19865451.596200.05.1WATER BASED16.02.19878161.176400.011.0WATER BASED23.12.198611501.166300.08.0WATER BASED29.12.198613501.176300.09.3WATER BASED29.12.198614181.196500.09.3WATER BASED29.12.198614181.196000.06.4WATER BASED29.12.198614181.256000.08.0WATER BASED29.12.198616821.506700.08.9WATER BASED29.12.198618971.609000.09.7WATER BASED30.12.198620301.637000.08.9WATER BASED02.01.198720301.635900.06.8WATER BASED02.01.198720301.636900.07.2WATER BASED05.01.198720301.637400.09.3WATER BASED05.01.198720301.636800.07.2WATER BASED05.01.198720811.637800.08.9WATERBASED02.01.198722001.204800.03.0WATER BASED13.02.198724631.205800.04.2WATER BASED12.01.198724631.206000.04.6WATER BASED14.01.198724631.205000.04.6WATER BASED08.01.198724631.205000.04.2WATER BASED09.01.198724631.205600.04.6WATER BASED12.01.198724631.206700.05.1WATER BASED12.01.198724631.205700.04.6WATER BASED13.01.198724631.205800.04.2WATER BASED15.01.198724631.205800.03.8WATER BASED16.01.198724701.206000.04.2WATER BASED19.01.198724721.256200.05.9WATER BASED06.01.198724911.254800.04.6WATER BASED07.01.198725361.204300.03.0WATER BASED09.02.198725361.205200.08.4WATER BASED09.02.198725361.205200.03.4WATER BASED10.02.198725361.205000.03.4WATER BASED11.02.198725361.205000.03.4WATER BASED12.02.198725651.204800.03.4WATER BASED09.02.198725651.205100.03.4WATER BASED02.02.198725651.205000.03.0WATER BASED03.02.198725651.205100.03.4WATER BASED04.02.198725651.204500.02.5WATER BASED05.02.198725651.204400.03.0WATER BASED09.02.198726401.206500.04.3WATERBASED27.01.198726401.207400.04.2WATER BASED28.01.198726401.207500.04.2WATER BASED29.01.198726401.204000.02.1WATER BASED30.01.198726400.004500.03.8WATERBASED02.02.198726401.204500.03.0WATER BASED02.02.198730831.208400.05.5WATER BASED19.01.198730831.207500.07.2WATER BASED19.01.198731191.207400.05.1WATER BASED21.01.198731251.209000.04.6WATER BASED21.01.198731971.206600.04.2WATER BASED22.01.198732201.207100.03.8WATER BASED23.01.198732201.207200.03.8WATER BASED26.01.198732201.206200.03.4WATER BASED26.01.198732201.206800.03.8WATER BASED26.01.1987