6407/7-1 S
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General information
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Wellbore history
GeneralWell 6407/7-1 S is located ca 30 km west of the Draugen field on the Njord A-structure in the southern part of the Halten Terrace. The apex of the A-structure is at about 2600 m MSL. The structure has a complex geology with dense faulting. The objective was to test for hydrocarbons in the structure, with the Middle and Early Jurassic as the primary and secondary targets. In addition, the well should obtain reservoir data from the Middle and Early Jurassic reservoir sandstones and establish a better stratigraphical, sedimentological, and structural knowledge of the area. The well should penetrate a deep reflector interpreted to be the "Top Middle Triassic Evaporite reflector". The prognosed total depth was 4025 m.Operations and resultsWildcat well 6407/7 1 S was spudded with the semi-submersible installation Polar Pioneer 19 October 1985 and was drilled to TD at 3950 m in Triassic rocks. Ca 30 days (17%) of the rig time was down time. Major causes for this were sub sea problems with orienting the temporary guide base, bad weather, and fishing for various objects and stuck tools. In addition the section from ca 746 to 1177 m required wiper trips and a lot of reaming to clean the hole. This added several days to the drilling time. The well was vertical down to 1177 m, it built deviation angle up to maximum 9.8 deg at 1460 m, and had a deviation between 9.8 and 3.0 deg from there to TD. The well was drilled with spud mud down to 1172 m, with KCl/polymer mud from 1172 m to 2710 m, with gel/polymer mud from 2710 m to 3601 m, and with gel/lignosulphonate mud from 3610 m to TD.The top of the reservoir came in at 2759 m, 70.5 m higher than prognosed. Oil was discovered in three separate reservoir units. The upper reservoir (2759 - 2783.5 m) consisted of sandstones belonging to the Fangst Group and Ror Formation. Relative pressure in this unit was 1.35 g/cc. The main reservoir (2839 -2988 m) consisted of sandstones belonging to the Tilje Formation. Relative pressure was 1.40 g/cc. This reservoir tested 730 and 711 Sm3 oil /day in two tests with a maximum rate of 1400 Sm3 oil /day. The oil was found to be under saturated. The lower reservoir (3017 - 3038 m) consisted of sandstones belonging to the Åre Formation. Total net pay in the reservoirs using porosity > 13%, volume of shale <40%, and < 60% water saturation was 130 m. The OWC was estimated to be at 3045 m.Oil shows of poor quality were observed on sand/sandstone (1-10 % of cuttings) in the Shetland Group from 2090 to 2165 m. Oil shows of poor to moderate quality were observed on siltstones recovered from CST run in the Viking Group at 2699 to 2711 m. Oil shows of poor to moderate quality restricted to porous sandstone only were observed in the Garn Formation from 2756 to 2780 m. Fair to good shows on porous coarse sandstone were observed in the Tilje/Åre Formations at 2837 to 3032 m. Shows of poor quality, again restricted to predominantly porous, coarse sandstone were observed in the Åre Formation at 3047 to 3082 m. The oil/water contact was defined from the logs to be between 3003 and 3082.5 m, while RFT data showed an oil/water contact between 3016 and 3045 m. The structural closure with estimated OWC at 3045 m was approximately 49 km2.The deep seismic reflector interpreted as "Top middle Triassic Evaporite reflector", was caused by two lithological sequences at 3828 m in the Red Beds, which created a composite strong seismic signal.16 cores were cut in the interval 2713 to 3118 m. Core 1 was cut in the Melke Formation, core 2 in the Garn Formation, while the remaining cores were cut in the Båt Group. An RFT segregated sample was taken at 2959.5 m (2945.2 m TVD RKB). It contained oil and gas with GOR = 241.7 Sm3/m3, BOB = 1.8358, stock tank oil density = 835.4 kg/m3, and gas gravity = 0.841 (air = 1).The well was permanently abandoned on 7 April 1986 as an oil and gas discovery.TestingFive drill stem tests were performed.DST 1 tested the interval 3099.5 - 3113.5 m in the Åre Formation. It produced 4.4 m3 water /day through a 25.4 mm choke. Maximum bottom-hole temperature was 114.8 deg C.DST 2 tested the interval 3022.9 - 3034.4 m in the uppermost Åre Formation. It produced 85 Sm3 oil /day through a 25.4 mm choke. GOR was 229 Sm3/Sm3, oil density was 0.832 g/cm3, and gas gravity was 0.800 (air = 1). Maximum bottom-hole temperature was 111.5 deg C.DST 3 tested the interval 2946.5 - 2973.0 m in the Tilje Formation. It produced 711 Sm3 oil /day through a 12.7 mm choke. GOR was 202 Sm3/Sm3, oil density was 0.825 g/cm3, and gas gravity was 0.700 (air = 1) . Maximum bottom-hole temperature was 114.7 deg C.DST 4 tested the interval 2840 - 2886 m in the uppermost Tilje Formation. It produced 730 Sm3 oil /day through a 12.7 mm choke. GOR was 202 Sm3/Sm3, oil density was 0.825 g/cm3, and gas gravity was 0.693 (air = 1). Maximum bottom-hole temperature was 113 deg C.DST 5 tested the interval 2758 - 2781 m in the Garn and upper Ror Formations. It produced 818 Sm3 oil /day through a 25.4 mm choke. GOR was 220 Sm3/Sm3 oil density was 0.823 g/cm3, and gas gravity was 0.732 (air = 1). Maximum bottom-hole temperature was 109.3 deg 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]420.003950.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom12713.02726.1[m ]22760.02770.7[m ]32772.02781.3[m ]42783.02801.9[m ]52804.02832.7[m ]62844.02854.8[m ]72871.02892.5[m ]82895.02922.8[m ]92923.02951.0[m ]102951.02970.0[m ]112970.02988.7[m ]122988.73013.3[m ]133013.53040.9[m ]143052.03060.2[m ]153063.03083.7[m ]163090.53118.0[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]314.6Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
Core photos
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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 availableDSTDST23022.903034.40OIL08.03.1986 - 00:00YESDSTDST32946.502973.00OIL16.03.1986 - 00:00YESDSTDST42840.002886.0023.03.1986 - 00:00YESDSTDST52758.002781.0030.03.1986 - 00:00YES -
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 typeCONDUCTOR30441.036443.00.00LOTSURF.COND.201130.0261172.00.00LOTINTERM.13 3/81890.017 1/21917.00.00LOTINTERM.9 5/82700.012 1/42710.00.00LOTINTERM.73729.08 3/83756.00.00LOTOPEN HOLE3950.063950.00.00LOT -
Drill stem tests (DST)
Drill stem tests (DST) Test numberFrom depth MD
[m]To depth MD
[m]Choke size
[mm]1.03100311425.42.03023303425.43.02947297312.74.02840288612.75.02758278125.4Drill stem tests (DST) Test numberFinal shut-in pressure
[MPa]Final flow pressure
[MPa]Bottom hole pressure
[MPa]Downhole temperature
[°C]1.02.03.04.05.0Drill stem tests (DST) Test numberOil
[Sm3/day]Gas
[Sm3/day]Oil density
[g/cm3]Gas grav. rel.airGOR
[m3/m3]1.02.085190000.8320.8002293.02101470000.8240.7072084.02041480000.8250.6932025.02211700000.8230.732220 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CBL VDL5001892CBL VDL16002703CBL VDL24003733CET24003733CST11901898CST19002336CST23562711CST27043750CST37623901CST37623941DIS LSS GR SP3533951DLL MSFL GR SP18513748LDL CNL CAL GR4203936RFT20022708RFT27602989RFT29083234S MDT GR18883940VSP6873750 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit35335310811739173919712682269626962706272127592759277327732839301731833277 -
Geochemical information
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Documents – reported by the production licence (period for duty of secrecy expired)
Documents – reported by the production licence (period for duty of secrecy expired) Document nameDocument formatDocument size [MB]pdf15.86pdf4.83 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured3751.04WATER BASED20.10.19853801.0799.099.0XXX07.04.19863801.0799.099.0XXXX07.04.19864431.04WATER BASED27.10.19854431.04WATER BASED20.10.19854431.04WATER BASED21.10.19854431.04WATER BASED22.10.19854431.04WATER BASED24.10.19855941.10WATER BASED29.10.19859451.06WATER BASED29.10.198511721.07WATER BASED31.10.198511721.07WATER BASED03.11.198511721.10WATER BASED05.11.198511721.16WATER BASED10.11.198511721.16WATER BASED12.11.198511721.2020.013.0WATER BASED13.11.198511721.07WATER BASED04.11.198511721.2020.013.0WATER BASED17.11.198511791.2118.010.0WATER BASED17.11.198512001.2111.010.0WATER BASED17.11.198513681.2122.014.0WATER BASED18.11.198514031.3022.011.0WATER BASED19.11.198514111.3022.012.0WATER BASED20.11.198516521.6032.015.0WATER BASED25.11.198516521.6525.014.0WATER BASED25.11.198516521.6530.015.0WATER BASED25.11.198516871.6530.015.0WATER BASED25.11.198519171.6837.012.0WATER BASED26.11.198519171.6835.014.0WATER BASED27.11.198519171.6831.012.0WATER BASED28.11.198519171.6831.012.0WATER BASED01.12.198519171.7135.011.0WATER BASED01.12.198519651.7136.08.0WATER BASED04.12.198521271.7140.013.0WATER BASED04.12.198521491.7130.09.0WATER BASED03.12.198522721.7131.010.0WATER BASED05.12.198522841.7130.09.0WATER BASED08.12.198522951.6326.07.0WATER BASED08.12.198523881.6334.010.0WATER BASED08.12.198525061.6528.08.0WATER BASED10.12.198525281.6529.08.0WATER BASED11.12.198526051.6526.09.0WATER BASED12.12.198526831.6526.010.0WATER BASED15.12.198527101.6525.011.0WATER BASED15.12.198527101.6525.010.0WATER BASED18.12.198527101.6528.07.0WATER BASED19.12.198527101.6528.07.0WATER BASED22.12.198527101.6525.010.0WATER BASED15.12.198527131.4419.07.0WATER BASED22.12.198527271.3817.07.0WATER BASED22.12.198527281.4728.016.0WATER BASED03.04.198627281.4612.010.0WATER BASED07.04.198627601.3818.08.0WATER BASED23.12.198527721.3818.07.0WATER BASED26.12.198527831.3816.07.0WATER BASED26.12.198528111.3818.08.0WATER BASED26.12.198528321.3817.09.0WATER BASED29.12.198528331.495.01.0BRINE02.04.198628331.545.01.0BRINE25.03.198628361.3816.08.0WATER BASED29.12.198528441.5519.08.0WATER BASED29.12.198528711.5520.09.0WATER BASED30.12.198528951.5521.07.0WATER BASED01.01.198629231.5518.06.0WATER BASED01.01.198629351.545.01.0BRINE21.03.198629351.545.01.0BRINE24.03.198629351.545.01.0BRINE24.03.198629351.545.01.0BRINE26.03.198629351.545.01.0BRINE25.03.198629511.5523.010.0WATER BASED02.01.198629881.5521.09.0WATER BASED05.01.198629881.5522.08.0WATER BASED05.01.198630131.5520.09.0WATER BASED05.01.198630131.5520.09.0WATER BASED05.01.198630131.5522.08.0WATER BASED07.01.198630131.5518.07.0WATER BASED08.01.198630161.555.01.0BRINE17.03.198630161.565.01.0BRINE19.03.198630161.545.01.0BRINE17.03.198630411.5519.07.0WATER BASED09.01.198630521.5518.08.0WATER BASED13.01.198630631.5519.08.0WATER BASED13.01.198630901.5519.08.0WATER BASED13.01.198630941.495.01.0BRINE03.03.198630941.585.01.0BRINE05.03.198630941.575.01.0BRINE06.03.198630941.575.01.0BRINE07.03.198630941.575.01.0BRINE11.03.198630941.585.01.0BRINE08.03.198630941.565.01.0BRINE12.03.198630941.565.01.0BRINE13.03.198630941.555.01.0BRINE14.03.198630941.585.01.0BRINE04.03.198631181.5124.08.0WATER BASED13.01.198631351.4921.08.0WATER BASED15.01.198631571.49WATER BASED24.02.198631571.495.01.0BRINE25.02.198631571.495.01.0BRINE26.02.198631571.495.01.0BRINE27.02.198631571.495.01.0BRINE28.02.198631571.495.01.0BRINE03.03.198631571.4916.06.0WATER BASED24.02.198632181.4924.011.0WATER BASED15.01.198632341.4921.010.0WATER BASED19.01.198632341.4922.011.0WATER BASED19.01.198633181.4923.011.0WATER BASED19.01.198633671.4922.09.0WATER BASED19.01.198633671.4921.08.0WATER BASED19.01.198633891.4919.08.0WATER BASED22.01.198634001.4922.09.0WATER BASED29.01.198634041.4922.010.0WATER BASED03.02.198634091.4923.09.0WATER BASED03.02.198635501.4923.012.0WATER BASED03.02.198636011.4923.012.0WATER BASED03.02.198636481.4915.06.0WATER BASED19.02.198636541.4920.013.0WATER BASED03.02.198637111.4915.07.0WATER BASED28.01.198637111.4915.07.0WATER BASED03.02.198637501.4916.06.0WATER BASED28.01.198637501.4916.06.0WATER BASED30.01.198637501.4916.06.0WATER BASED04.02.198637551.4916.06.0WATER BASED05.02.198637551.5016.05.0WATER BASED07.02.198637551.5016.06.0WATER BASED11.02.198637551.5015.06.0WATER BASED11.02.198637551.4916.06.0WATER BASED06.02.198637551.4916.05.0WATER BASED11.02.198637561.4915.08.0WATER BASED12.02.198637561.4913.07.0WATER BASED13.02.198637581.4913.06.0WATER BASED21.02.198637711.4918.08.0WATER BASED13.02.198637871.4915.08.0WATER BASED17.02.198638891.4915.07.0WATER BASED17.02.198639501.4916.06.0WATER BASED17.02.198639501.4916.06.0WATER BASED18.02.1986 -
Palynological slides at the Norwegian Offshore Directorate
Palynological slides at the Norwegian Offshore Directorate Sample depthDepth unitSample typeLaboratory1805.2[m]SWCSTRAT?1824.8[m]SWCSTRAT?1839.9[m]SWCSTRAT?1844.9[m]SWCSTRAT?1898.1[m]SWCSTRAT?1900.2[m]SWCSTRAT?1927.0[m]SWCSTRAT?1946.0[m]SWCSTRAT?1959.0[m]SWCSTRAT?1981.0[m]SWCSTRAT?2000.0[m]SWCSTRAT?2019.0[m]SWCSTRAT?2039.5[m]SWCSTRAT?2058.0[m]SWCSTRAT?2078.0[m]SWCSTRAT?2100.0[m]SWCSTRAT?2121.0[m]SWCSTRAT?2140.0[m]SWCSTRAT?2160.0[m]SWCSTRAT?2190.0[m]SWCSTRAT?2220.0[m]SWCSTRAT?2231.0[m]SWCSTRAT?2249.3[m]SWCSTRAT?2276.5[m]SWCSTRAT?2295.0[m]SWCSTRAT?2314.0[m]SWCSTRAT?2336.5[m]SWCSTRAT?2425.0[m]SWCSTRAT?2449.0[m]SWCSTRAT?2493.5[m]SWCSTRAT?2550.0[m]SWCSTRAT?2590.0[m]SWCSTRAT?2610.0[m]SWCSTRAT?2630.0[m]SWCSTRAT?2649.0[m]SWCSTRAT?2670.0[m]SWCSTRAT?2693.0[m]SWCSTRAT?2697.0[m]DCPETROSTR2699.0[m]SWCSTRAT2702.0[m]SWCSTRAT2702.0[m]DCPETROSTR2704.0[m]SWCSTRAT2710.0[m]DCPETROSTR2711.0[m]SWCSTRAT2717.1[m]COD2717.5[m]CPETROSTR2720.1[m]COD2725.1[m]COD2725.6[m]CPETROSTR2735.0[m]SWCSTRAT2747.0[m]SWCSTRAT2757.0[m]SWCSTRAT2772.1[m]COD2784.9[m]COD2789.9[m]COD2798.6[m]COD2804.8[m]COD2810.9[m]COD2816.9[m]COD2822.7[m]COD2828.3[m]COD2837.0[m]SWCSTRAT2862.0[m]SWCSTRAT3045.0[m]SWCSTRAT3138.0[m]SWCSTRAT3183.0[m]SWCSTRAT3247.0[m]SWCSTRAT3333.0[m]SWCSTRAT3400.0[m]SWCSTRAT3518.0[m]SWCSTRAT3578.0[m]SWCSTRAT3611.0[m]SWCSTRAT3640.0[m]SWCSTRAT3706.0[m]SWCSTRAT