30/6-31 S
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General information
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Wellbore history
GeneralWell 30/6-31 S was drilled to test the Helleneset prospect between the Oseberg and Brage fields on the Oseberg Fault block in the North Sea. The primary objective was to test the hydrocarbon potential in Callovian Intra-Heather Formation sandstones.Operations and resultsA shallow gas pilot hole 30/6-U-28 was spudded 18 m south of the main well location on 9 March 2020. Due to weather and other problems, this well was aborted after drilling down to 511 m. A second pilot hole (drilled with 8 ½” BHA) was then drilled from 30/6-31 S well location down to 1120 m. Based on the log interpretation, flow checks, sonar and ROV observations, there were no shallow gas observed from these pilot holes.Wildcat well 30/6-31 S was spudded with the semi-submersible installation West Hercules on 4 April 2020 and drilled to TD at 2852 m (2830.4 m TVD) in the Middle Jurassic Ness Formation. Operations proceeded without significant problems. The well was drilled with seawater and hi-vis pills down to 1120 m, with Versatec oil-based mud from 1120 m to 2649 m, and with Exploradrill oil-based mud from 2649 m to TD.High formation gas levels were observed in limestones within Shetland Group in the 12 ¼” section. The limestones are correlated with Shetland limestone in Oseberg Main Field. A gas chimney is observed in the seismic, showing potential leak to overburden and which may charge the Shetland limestone at the well location.The targeted Jurassic Callovian syn-rift reservoir was poorly developed and appear as thin cemented sands without any indication of hydrocarbons from the logs, gas, or cuttings. A thin Tarbert Formation was drilled, and no hydrocarbon indications were encountered. The pressure measurement acquired in Heather-Callovian, Tarbert and Ness sand concluded a depleted pressure (100 bar depletion in the Ness Formation.).No cores were cut. No fluid sample was taken.The well was permanently abandoned on 25 April 2020 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]1130.002850.00 -
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 typeCONDUCTOR36187.042189.00.00SURF.COND.13 3/81113.017 1/21120.01.67LOTPILOT HOLE1120.08 1/21120.00.00LINER9 5/82649.012 1/42649.01.74LOTOPEN HOLE2852.08 1/22852.00.00 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]MWD - AV TS1891120MWD - AV TS26492852MWD - ES SS TS1872649XPT HNGS AIT PEX26492852 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit13868588010332069208520852136219223052313233423342416242524832483251125142536253625822737281228122817 -
Palynological slides at the Norwegian Offshore Directorate
Palynological slides at the Norwegian Offshore Directorate Sample depthDepth unitSample typeLaboratory1130.0[m]DCAPT1170.0[m]DCAPT1210.0[m]DCAPT1250.0[m]DCAPT1290.0[m]DCAPT1330.0[m]DCAPT1370.0[m]DCAPT1410.0[m]DCAPT1450.0[m]DCAPT1490.0[m]DCAPT1530.0[m]DCAPT1570.0[m]DCAPT1610.0[m]DCAPT1650.0[m]DCAPT1680.0[m]DCAPT2100.0[m]DCAPT2120.0[m]DCAPT2140.0[m]DCAPT2160.0[m]DCAPT2180.0[m]DCAPT2200.0[m]DCAPT2260.0[m]DCAPT2280.0[m]DCAPT2300.0[m]DCAPT2320.0[m]DCAPT2370.0[m]DCAPT2400.0[m]DCAPT2430.0[m]DCAPT2510.0[m]DCAPT2515.0[m]DCAPT2520.0[m]DCAPT2525.0[m]DCAPT2540.0[m]DCAPT2545.0[m]DCAPT2550.0[m]DCAPT2555.0[m]DCAPT2560.0[m]DCAPT2565.0[m]DCAPT2570.0[m]DCAPT2575.0[m]DCAPT2580.0[m]DCAPT2585.0[m]DCAPT2590.0[m]DCAPT2595.0[m]DCAPT2600.0[m]DCAPT2605.0[m]DCAPT2610.0[m]DCAPT2620.0[m]DCAPT2625.0[m]DCAPT2630.0[m]DCAPT2635.0[m]DCAPT2640.0[m]DCAPT2645.0[m]DCAPT2652.0[m]DCAPT2664.0[m]DCAPT2670.0[m]DCAPT2676.0[m]DCAPT2682.0[m]DCAPT2688.0[m]DCAPT2694.0[m]DCAPT2700.0[m]DCAPT2706.0[m]DCAPT2712.0[m]DCAPT2718.0[m]DCAPT2724.0[m]DCAPT2730.0[m]DCAPT2736.0[m]DCAPT2742.0[m]DCAPT2748.0[m]DCAPT2754.0[m]DCAPT2760.0[m]DCAPT2766.0[m]DCAPT2772.0[m]DCAPT2784.0[m]DCAPT2790.0[m]DCAPT2796.0[m]DCAPT2802.0[m]DCAPT2808.0[m]DCAPT2814.0[m]DCAPT2820.0[m]DCAPT2826.0[m]DCAPT2832.0[m]DCAPT2838.0[m]DCAPT2844.0[m]DCAPT2850.0[m]DCAPT