25/8-19 S
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General information
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Wellbore history
Operations and resultsA 9-7/8" shallow gas pilot hole was drilled to 1015 m in the Hordaland Group, just below the Skade Formation. No shallow gas was encountered.Wildcat well 25/8-19 S was spudded with the semi-submersible installation Deepsea Bergen on 2 November 2019 and drilled to TD at 2760 m (2545 m TVD) m in Basement rock. Operations proceeded mostly as planned, but while drilling the final 6" hole to final TD the top drive service loop was damaged by a fire. Waiting for new parts and repairs caused one week NPT. The well was drilled with seawater and hi-vis pills down to 1015 m and with RheGuard oil-based mud from 1015 m to TD.No injectite sandstone was encountered in the Eocene. Thin oil-bearing sandstone layers were found in the Paleocene Heimdal Formation, confirmed by MDT sampling. The Ty Formation massive sandstones were water-bearing, but sidewall cores indicated shows above OBM in the more porous intervals (5 - 12 % porosity). The Ty Formation sands rest unconformably on the Early Jurassic Amundsen Formation. The Amundsen Formation is a ca 20 m thick claystone unit separating the massive Ty sandstones from massive Upper Statfjord sandstones. The Upper and Middle Statfjord Group sandstones were water-bearing down to 2356 m, but good shows with bleeding oil was seen on the core from this section. Oil-bearing sandstones were encountered in the Lower Statfjord unit and pressure gradients indicated an OWC at 2386 m (2233.3 m TVD). Below this OWC an isolated pocket of oil was proven by sampling in a thin sand at 409.5 m. A 34-metre gas column in sandstone with moderate to good reservoir quality lies over an oil column of minimum 45 metres in sandstones in the Skagerrak Formation. The OWC was not encountered. Weathered and partly fractured crystalline basement is oil-bearing with a column a minimum of 41 metres.Four cores were cut. Core 1 was cut from 2252.6 to 2277.3 m in the Statfjord Group with 99.8% recovery. Cores 2, 3 and 4 were cut in succession from 2575 to 2662.2 m in the Skagerrak Formation with 99.7 to 101.2% recoveries. MDT fluid sample were taken at 2036.79 m (Oil), 2255 m (water), 2382.94 m (oil), 2385.4 m (water), 2409.5 m (oil), 2428.49 m (water), 2596.7 m (gas), 2598.75 m (oil), 2611.5 m (oil), 2688.02 m (oil), and 2735.02 m (oil). Contamination with mud filtrate in the samples varied from 3.6 to 36 %wt. The least contaminated oil samples are from 2036,79 m, 2382,94 m and 2611,5 m.The well was plugged back for side-tracking of 25/8-19 A on 30 December 2019. It is classified as an oil and gas discovery 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]1020.002760.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom12252.62277.3[m ]22575.02603.5[m ]32603.52632.9[m ]42632.92662.7[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]112.4Cores 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 availableMDT0.000.00YESMDT2036.790.00OIL30.11.2019 - 00:00YESMDT2382.940.00OIL09.02.2020 - 00:00YESMDT2409.530.00OIL05.12.2019 - 00:00YESMDT2611.500.00OIL05.12.2019 - 00:00YESMDT2688.020.00OIL23.12.2019 - 00:00YESMDT2735.020.00OIL23.12.2019 - 00:00YES -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit149149488679679998112811541154116419361992202720612113212322272227224522452263243424342716 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]LWD - DIR PWD GR RES1491015LWD - DIR PWD GR RES SON1491015LWD - GR DIR PWD DEN NEU RES SON26752760LWD - GR PWD DIR DEN NEU RES SON10152675MDT20012670MDT DPS26862749MDT MINIDST20322666MSCT20012670MSCT26802758NFXT CMR20012670TLD HGNS26582768TLD HGNS PPC MAST PPC20012670UBI NGI26682760USIT CBL12211957XL ROCK2001270ZAIT MAST26532769ZAIT NGI20012670 -
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 typeCONDUCTOR30215.036215.00.00SURF.COND.201009.5261009.51.74FITINTERM.9 5/81914.412 1/41914.01.93LOTLINER72473.08 1/22473.01.50FITOPEN HOLE2545.062545.00.00 -
Thin sections at the Norwegian Offshore Directorate
Thin sections at the Norwegian Offshore Directorate DepthUnit2310.28[m ]3228.42[m ]2350.31[m ]2364.23[m ]2395.30[m ]2410.65[m ]2415.68[m ]2427.51[m ]2442.33[m ]2454.18[m ]2475.91[m ]2499.50[m ]2517.86[m ]2545.75[m ]2563.19[m ]2682.30[m ]2685.02[m ]2726.47[m ]2727.00[m ]2728.00[m ]2730.01[m ]2733.54[m ]2736.61[m ]2739.51[m ]2743.06[m ]2745.48[m ]2747.00[m ]2747.50[m ]2749.34[m ]2751.00[m ]2752.00[m ]2755.52[m ]2758.54[m ]2725.53[m ]2722.50[m ]2719.98[m ]2715.48[m ]2710.01[m ]2695.99[m ]2686.50[m ]2690.50[m ]2680.00[m ]2293.33[m ]2281.30[m ]2252.18[m ]2247.66[m ]2244.15[m ]2239.13[m ]2226.09[m ]2223.09[m ]2219.41[m ]2214.16[m ]2199.31[m ]2182.47[m ]2156.68[m ]2126.69[m ]2117.93[m ]2050.85[m ]2036.79[m ]2034.77[m ]2017.74[m ]2662.75[m ]2661.51[m ]2660.22[m ]2659.35[m ]2658.60[m ]2657.34[m ]2656.37[m ]2655.60[m ]2654.82[m ]2653.89[m ]2652.82[m ]2652.08[m ]2651.12[m ]2649.75[m ]2647.35[m ]2645.37[m ]2642.91[m ]2638.87[m ]2637.90[m ]2637.40[m ]2636.41[m ]2635.11[m ]2631.67[m ]2630.50[m ]2628.82[m ]2627.20[m ]2626.37[m ]2625.38[m ]2624.48[m ]2623.90[m ]2623.15[m ]2622.81[m ]2622.08[m ]2621.40[m ]2620.75[m ]2618.60[m ]2616.60[m ]2615.85[m ]2615.06[m ]2614.50[m ]2613.75[m ]2613.25[m ]2612.50[m ]2611.75[m ]2611.12[m ]2611.05[m ]2610.50[m ]2610.28[m ]2609.48[m ]2608.75[m ]2608.50[m ]2607.80[m ]2607.60[m ]2606.50[m ]2606.21[m ]2605.50[m ]2604.55[m ]2603.75[m ]2603.41[m ]2601.75[m ]2601.02[m ]2600.25[m ]2599.95[m ]2599.25[m ]2598.60[m ]2598.02[m ]2597.25[m ]2596.75[m ]2595.95[m ]2595.50[m ]1.00[m ]2594.95[m ]2594.75[m ]2593.50[m ]2592.50[m ]2591.51[m ]2588.77[m ]2587.02[m ]2586.02[m ]2585.02[m ]2584.95[m ]2583.25[m ]2582.50[m ]2581.95[m ]2580.02[m ]2579.50[m ]2579.02[m ]2578.45[m ]2577.53[m ]2576.73[m ]2576.02[m ]2575.03[m ]2276.24[m ]2275.40[m ]2274.49[m ]2272.20[m ]2271.50[m ]2271.02[m ]2270.51[m ]2269.50[m ]2268.25[m ]2267.28[m ]2266.75[m ]2260.02[m ]2265.02[m ]2264.62[m ]2264.25[m ]2263.50[m ]2262.02[m ]2261.50[m ]2260.40[m ]2259.50[m ]2257.25[m ]2255.03[m ]2254.03[m ]2252.85[m ]2252.62[m ]