6305/9-2
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General information
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Wellbore history
GeneralThe exploration well 6305/9-2 is located in the northern part of block 6305/9, 25 km east of the Ormen Lange field. The main objective was to test the presence of hydrocarbons in the Dovregubben prospect, in the Palaeocene Tang Formation channel sandstones. Secondary prospects were identified in the Paleocene Egga Formation and in the Late Cretaceous Springar Formation.Operations and resultsWildcat well 6305/9-2 was spudded with the semi-submersible installation Aker Barents on 26 December 2010 and drilled to TD at 3075 m in the Late Cretaceous Springar Formation. After the 36" section a 9 7/8" pilot hole was drilled from 381 m to 496 m using seawater and hi-vis pills to check for shallow gas. Shallow gas was detected in a sandy interval from 484 m to 486 m. The pilot was cemented and opened up/drilled with 26" BHA down to 477 m where 20" casing was set, shallower than planned due to the shallow gas. While drilling the succeeding 17 1/2" section gas peaks (drilled gas) were recorded at 485 m (2.8%), 577 m (2.7%) and 636 m (2.4%) in sandy intervals. The well took significantly longer time than planned. The main causes for this was hole problems (134.5 hrs) and WOW (472.5 hrs, of which 386.5 hrs occurred after pulling riser and BOP, before final anchor handling and abandonment). The well was drilled with seawater and bentonite down to 477 m, with seawater and polymer mud from 477 m to 671 m, and with Glydril mud (3.5 - 5.1% glycol) from 671 m to TD.The geology and the depth prognosis of the well came in very much as prognosed. The Tang Formation sandstones were thinner than expected, and with poorer reservoir quality. The secondary targets contained Egga Formation reservoir and thin Springar Formation sand units with reservoir properties as expected. Wire line logs proved generally poor reservoir quality, though porosities as high as 25% were seen in thin intervals in the Springar Formation. The Intra Tang Formation channel sandstone had a gross thickness of 15 m with 3.4 m net reservoir.No hydrocarbon indications were observed in the well except in one cuttings sample at 3006 m where a weak spotty direct fluorescence was observed. This show was described as spotty yellow white direct fluorescence, no visible cut, trace dull yellow white fluorescence ring residue, no visible residue.No cores were cut and no wire line fluid samples were taken.The well was permanently abandoned on 13 March as a dry well.TestingNo drill stem test was performed. -
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]486.003073.00 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit314314140216541654242024202554298930163016 -
Geochemical information
Geochemical information Document nameDocument formatDocument size [MB]txt0.00txt0.02pdf0.28 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]MWD - PP ARCVIS4961255MWD - TELE ARCVIS435477MWD - TELE ARCVIS SONVIS386496MWD - TELE ARCVIS SONVIS ADNVIS12552751MWD - TELE PP314386MWD - TELE SONVIS GVR ECO27513075PEX HRLA28803060PEX HRLA MSIP17203075VSP12003060 -
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 typeCONDUCTOR30380.036381.00.00LOTSURF.COND.20476.026477.01.18LOTLINER16668.017 1/2671.01.30LOTINTERM.13 3/81249.017 1/21255.01.60LOTINTERM.9 5/82749.012 1/42751.01.89LOTOPEN HOLE3075.08 1/23075.00.00LOT -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured3141.046.0Spud Mud4251.2714.0Glydrill4761.046.0Spud Mud5721.1915.0Glydrill6671.0918.0CMC mud6701.0919.0CMC mud12151.2418.0Glydrill16671.3922.0Glydrill27511.4422.0Glydrill28731.3922.0Glydrill30751.3923.0Glydrill