6406/12-4 S
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General information
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Wellbore history
GeneralWell 6406/12-4 S was drilled on the flank of the Frøya High close to the southern end of the Halten Terrace in the Norwegian Sea. The exploration objective was to test Intra Melke sandstone in the Boomerang South West Prospect, younger than the reservoir in the Pil discovery. The well also had as appraisal objective to core the transition into the top of the Pil discovery reservoir close to the established oil-water contact.Operations and resultsWildcat well 6406/12-4 S was spudded with the semi-submersible installation Transocean Arctic on 23 June 2015 and drilled to TD at 4318 m (3882.9 m TVD) m in Late Jurassic Intra-Melke sandstone. The well was drilled vertical down to 1203 m. From 1203 m to 3660 m, the well was drilled deviated with a sail angle of 41°. From there and through the reservoir to final TD the sail angle was changed to ca 7°. Due to a highly overbalanced mud weight during drilling in the 8 1/2" section, a significant drill break was experienced in the Rogn Formation, with substantial mud losses to the formation at approximately 3746 m. This caused serious mud invasion into the formation. The well was drilled with seawater and sweeps down to 1210 m and with XP-07 oil based mud from 1210 m to TD.The well encountered 26 m of Rogn Formation of good quality at 3726 m. A 196 m thick package of Spekk shales and siltstones followed down to top Melke Formation at 3946 m. Small amounts of oil was recovered in an RCX fluid sample from the Rogn Formation. Both this oil and pressure data from the Rogn Formation were seriously affected by the mud invasion, making it difficult to conclude on the nature of the oil. The petrophysical logs indicated hydrocarbon saturations of up to 20% across the cored interval in the Melke Formation sandstone. No oil shows above the mud were recorded in the Rogn Formation. Weak oil shows were described on cores and cuttings throughout the Melke Formation and Intra Melke sandstones.A total of 41.95 m core was recovered in three cores from the interval 3941 to 3984.3 m (96.9% total recovery) across the base Spekk-top Melke boundary. An RCX fluid sample was taken at 3736 m (3281.3 m TVD) in the intra Spekk Formation sandstone. This sample contained 90 vol-% formation water, 5 vol-% mud filtrate and 5 vol-% reservoir oil. Further RCX samples recovered formation water at 3956.7 m, 3968.2 m, 3988.2 m and 4021.6 m in the Intra-Melke Formation sandstoneThe well was permanently abandoned on 17 August 2015.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]1210.004319.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom13941.03941.9[m ]23942.53950.5[m ]33950.73983.8[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]42.0Cores 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 availableMDT0.000.00BASE OILYESMDT0.000.00BASE OILYESMDT0.000.00BASE OILYES -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit3453451085116011601850185019682215221523172539325132513478369937263726375339463951 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]HDIL XMAC ORIT ZDL CN DSL3604072HDIL ZMAC ORIT ZDL CN DSL36504322MREX FLEX DSL36504060MWD - ATK ZTKR ZTKG COP OTK SDTK22484318MWD - DIR PWD1415MWD - DIR PWD GR RES4151210MWD - DIR PWD GR RES SON12102248PCOR37264021PCOR39124267RCX37304025RCX40694308UXPL ORIT GXPL GR36504060VSP17454310 -
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 typeCONDUCTOR30411.336415.00.00SURF.COND.201203.5261210.01.66FITPILOT HOLE1210.09 7/81210.00.00INTERM.13 3/82242.017 1/22248.01.69FITINTERM.9 5/83652.012 1/43660.01.79FITOPEN HOLE4318.08 1/24318.00.00 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured3441.3421.0WBM11531.5435.0XP07 Low ECD12131.4921.0XP-07 Low ECD OBM13161.5430.0XP07 Low ECD17431.5124.0XP-07 Low ECD OBM19351.5429.0XP-07 Low ECD OBM24631.5431.0XP-07 Low ECD OBM29181.5434.0XP-07 Low ECD OBM35381.5428.0XP07 Low ECD36601.4733.0XP-07 Low ECD OBM36601.5433.0XP-07 Low ECD OBM37461.4936.0XP-07 Low ECD39421.3923.0XP07 Low ECD43181.3933.0XP07 Low ECD43181.3927.0XP07 Low ECD