35/1-2 S
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General information
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Wellbore history
GeneralWell 35/1-2 S was drilled on the Soleie Graben Prospect on the Tampen Spur between the Knarr and Peon discoveries in the northern North Sea. The main objective was to prove commercial hydrocarbon accumulation in the Early Jurassic Cook Formation. Secondary objectives were to drill through leads in the Paleocene Lista Formation and in the Cretaceous Kyrre Formation. The well commitment was to drill 50 m into the Statfjord Formation.Operations and resultsDrilling was performed with the semi-submersible installation Transocean Leader. A pilot hole 35/1-U-1 was drilled first to check for shallow gas. No gas was seen. The main well was spudded 15 m south-east of the pilot and drilled to TD in 26" section. Casing and conductor were run, but due to a leak in the casing the well was abandoned and re-named 35/1-U-2. Wildcat well 35/1-2 S was spudded 15 m north-east of the abandoned on 12 September 2010 and drilled to TD at 4202 m (4122 m TVD) in the Early Jurassic Statfjord Formation. The Lista Formation was drilled with a 17" hole and opened up to 20" after the wire line logging was performed. Due to interbedded clay and hard limestone layers 8 runs were necessary to under ream the section. The well was drilled with sea water down to 1293 m, with Performadril mud from 1293 m to 2358 m, with XP-07 oil based mud from 2358 m to 3698 m, and with Low ECD-HTHP oil based mud from 3698 m to TD.The tops in the overburden came in within the given uncertainties. Bigger differences were seen below the BCU. Five meters of Cromer Knoll Group were drilled before the Heather Formation was encountered at 3624 m. The Viking Group was thinner than expected and no Brent Group Equivalent was identified, therefore the Heather was directly in contact with the Drake Formation, which then came in 192 m shallower than prognosed. The Cook Formation came in 30 m shallower than prognosed and was thinner than expected, leading to a 75 m shallower top Statfjord Formation than expected. All the potential reservoirs and leads were dry and no hydrocarbon shows were observed.Only GR-Resistivity-Density-Neutron-Sonic and sidewall cores were run on wire line. Pressure points were taken while drilling. No cores were cut and no wire line fluid samples were taken.The well was permanently abandoned on 19 December 2010 and classified as dry.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]1290.004201.00 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit43316282001200120492062215121552155227736083618361836243624363836383923396139834142 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]EMS EDTC GR LEHQT 6-ARM-CAL12752067GPIT EMS EDTC GR LEHQT 6-ARM-CAL12751751MSCT39264171MWD LWD - ARCVRES PP5322355MWD LWD - ARCVRES6 STET TELE36954202MWD LWD - ARCVRES8 PP STET PD G23043695MWD LWD - POWERPULSE432532PEX DSI AIT23042869PEX DSI AIT35944202PEX HRLA DSI GR12762330PWX DSI AIT28493695VSP5672325 -
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 typeCONDUCTOR30528.036532.00.00LOTSURF.COND.201276.0261293.01.60LOTINTERM.162304.0202358.01.81LOTINTERM.142849.017 1/22875.01.85LOTLINER9 7/83694.012 1/43698.02.06LOTOPEN HOLE4202.08 1/24202.00.00LOT -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured12431.3517.0Spud Mud13441.4534.0Performadril16201.4534.0Performadril17761.4523.0Performadril20101.4528.0Performadril22641.4828.0Performadril23171.4328.0XP-07 - #1423351.4523.0Performadril23461.4836.0Performadril23551.4525.0Performadril28591.4126.0XP-07 - #1428691.4327.0XP-07 - #1428721.4125.0XP-07 - #1436951.7950.0XP-07 - #1436961.7953.0XP-07 - #1436981.9339.0OBM-Low ECD-HTHP42021.9834.0OBM-Low ECD-HTHP