36/7-4
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General information
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Wellbore history
Wellbore historyGeneralWell 36/7-4 was drilled to test the Cara prospect ca 5 km northeast of the Gjøa Field in the North Sea. The primary objective was to test for hydrocarbons in the Early Cretaceous Agat Formation.Operations and resultsWildcat well 36/7-4 was spudded with the semi-submersible installation Transocean Arctic on 18 July 2016 and drilled to TD at 2726 m in the Early Cretaceous Åsgard Formation. Operations proceeded without significant problems. The well was drilled with seawater and hi-vis sweeps down to 587 m and with KCl/glycol mud from 587 m to TD.Well 36/7-4 successfully penetrated 118.1 of hydrocarbon-bearing Agat Formation sandstone reservoir before reaching a final TD of 2726 m in the Åsgard Formation. The well proved a 51.7 m gas column in good quality reservoir, with a GOC at 2479.2 m. Oil was proven down to close to the base of the Agat sandstone at 2544.4 m, but the reservoir below 2492 m is of reduced quality with low permeability and poor production potential. No oil-water contact (OWC) was seen, neither from pressures, nor on logs or core.Three cores were cut from 2437 to 2555 m in the Agat Formation, including the Agat Formation basal conglomerates. MDT fluid samples were taken at 2440 m (gas), 2458.13 m (gas), 2484.03 m (oil), 2488 m (oil), 2536.61 m (oil), and 2544.4 m (oil/water).The well was permanently abandoned on 26 September 2016 as an oil and gas discovery.TestingA drill stem test was conducted from the gas column in the interval 2428 to 2470 m.Very good overall reservoir properties were proven. The maximum gas rate achieved was 1240000 Sm3/day, through a 72/64" fixed choke. The gas gravity was 0.6378 (air = 1). The condensate had a density of 0.801 g/cm3 (45.2 ºAPI). The Gas/Condensate Ratio was 15592 Sm3/Sm3. The gas had 0.5% CO2 and 0.2 ppm H2S. Measurements at the end of the main shut-in periods (up to 72 hrs) gave the most representative formation temperatures. The temperature at the gas-oil contact is estimated to 80.0 °C. -
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]590.002726.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom12436.92490.7[m ]22491.02499.7[m ]32499.72554.6[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]117.4Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit372372602602109212581258128520052215222023762376242825542620 -
Drill stem tests (DST)
Drill stem tests (DST) Test numberFrom depth MD
[m]To depth MD
[m]Choke size
[mm]1.02428247028.6Drill stem tests (DST) Test numberFinal shut-in pressure
[MPa]Final flow pressure
[MPa]Bottom hole pressure
[MPa]Downhole temperature
[°C]1.0Drill stem tests (DST) Test numberOil
[Sm3/day]Gas
[Sm3/day]Oil density
[g/cm3]Gas grav. rel.airGOR
[m3/m3]1.012400000.8010.63715592 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CMR ADT HRLA PEX ECS23642724FMI MSIP GR23642725MDT GR24292567MDT GR SP24352536MSCT SWC23782640MWD - DIR ECD373439MWD - GR DIR ECD RES439587MWD - GR DIR ECD RES SON487590MWD - GR DIR ECD RES SON5901710MWD - GR ECD RES SON DIR17102115MWD - GR ECD RES SON NEU POR DEN21152780MWD - GR RES ECD RES SON373587USIT CBL GR00VSP GR16892656 -
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 typeCONDUCTOR30439.036439.00.00SURF.COND.20583.026587.00.00PILOT HOLE587.09 7/8587.00.00590.0590.01.25LOTINTERM.13 3/81701.017 1/21710.00.001713.01713.01.50FITINTERM.9 5/82364.012 1/42370.00.002374.02374.01.48LOTLINER72663.08 1/22726.00.00 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured3721.039.0Sweeps4391.1540.0KCL/Polymer/Glycol4421.4936.0Kill/DIsplacment Mud5041.0313.0Sweeps5041.4934.0Kill/DIsplacment Mud5351.011.0Seawater5351.1719.0KCl mud5871.1540.0KCL/Polymer/Glycol5871.4934.0Kill/DIsplacment Mud5901.1525.0KCL/Polymer/Glycol9171.1624.0KCL/Polymer/Glycol10911.1724.0KCL/Polymer/Glycol12341.1623.0KCL/Polymer/Glycol14881.1722.0KCL/Polymer/Glycol15251.1625.0KCL/Polymer/Glycol17101.1726.0KCL/Polymer/Glycol17101.1527.0KCL/Polymer/Glycol21001.1917.0KCl mud21001.1717.0KCl mud21411.1720.0KCL/Polymer/GEM23741.1922.0KCL/Polymer/Glycol26651.192.0NaCl Brine26651.2117.0KCl Polymer GEM27261.1922.0KCL/Polymer/Glycol