6507/7-2
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General information
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Wellbore history
GeneralThe well 6507/7-2 was drilled in the northern part of the Haltenbanken area, some 190 km west of the Norwegian coast. It was drilled to evaluate the "B" prospect in the intensely faulted zone that lies at the intersection of the Nordland Ridge in the northeast and the Halten Terrace in the south. The prospect was in a southward plunging horst block formed by a Late Jurassic tensional fault system. The main reservoir interval was anticipated to be the Lower Jurassic sandstone of the Aldra (Tilje) Formation.Operations and resultsWildcat well 6507/7-2 was spudded with the semi-submersible installation Nortrym on 25 February 1985 and drilled to TD at 3262 m in Late Triassic sediments of the Åre Formation. No significant problems occurred during drilling operations, which went very much according to schedule. The seven-test program was however delayed approximately two weeks due to a premature firing of the Baker Tubing-Conveyed Perforating Guns while running in for DST 4. This necessitated the running of a protective string of 7" casing to cover the perforations (1062.5m to 1072.5m) and enable the testing program to be completed. Additional time was lost due to pulling and repairing the BOP stack after running the protective casing string. The well was drilled with sea water down to 1030 m and with gypsum mud from 1030 m to TD.Shetland Group sediments were resting directly on the Fangst Group, confirming heavy erosion at the crest of the structure as prognosed. The oldest dating of the Shetland Group was Santonian age, in sediments ca 5 m above top Fangst Group, while the youngest Fangst Group sediments were dated Toarcian-?Aalenian. At 2198 meters gas levels rose, indicating the top of the Jurassic sediments. Associated with the gas show was a rare dull-gold fluorescence on cuttings; however, no cut or staining was evident. The MWD gave little indication of sand through the Fangst Group and very little sand was seen in samples. The Ror Formation claystones separated the Fangst Group from the underlying Tilje formation.The Fangst and Båt groups were found hydrocarbon-bearing. Using gradients established from electric logs, RFT data, and fluid analysis the gas/oil contact was estimated to be at 2317.5 m. The oil/water contact was not as clear-cut. From logs it was placed at 2455, while the RFT data indicated an OWC between 2476 and 2482 m.Fourteen cores were cut in the Tilje Formation from 2283.5m to 2448.5m with an 84% recovery. The coring point was picked on the basis of prognosed depths, two earlier drilling breaks in claystones having been circulated out. Good oil shows were observed. There was good fluorescence to 2317m though little or no visible staining and cut was apparent. Visible oil with a good cut was apparent to 2439 meters, but the quality of show declined from this depth, with no fluorescence recorded below 2470 meters. Analysis of cores and logs indicated very good sandstone porosities and permeabilities throughout the interval. The low gas values through the reservoir were thought to reflect an overbalance of 3.5 - 4.5ppg which combined with increasing permeability caused flushing of the formation ahead of the bit.Four segregated RFT samples were taken at 2220.5 m (gas + water, mud and small amount of light coloured oil/condensate), 2303 m (gas + water, mud and small amount of light coloured oil/condensate), 2331.5 m (2.5 litres 29.8 deg API gravity oil with some gas) and 2382.7 m (9 litres of 22 deg API gravity oil with some water and gas).The well was permanently abandoned on 10 June 1985 as an oil and gas discovery.TestingSeven drill stem tests were undertaken. DST 1 was performed in the water zone within the Tilje Formation from 2521 to 2529 m. Four further tests were performed in the Tilje Formation with DST 2 (2417 - 2439 m), 3 (2356.5 - 2376 m) and 4A (2330 - 2340 m) flowing oil and DST 5 (2290 - 2310 m) gas/condensate. DST 6 (2232 - 2245 m) in the Ror Formation produced gas/condensate, and DST 7 in the Fangst Group, 2203 to 2222 m, produced predominantly gas. At stabilized conditions using various chokes sizes the cumulative peak production of oil was 2095 Sm3/day. Oil gravity ranged from 0.922 g/cm3 (22 deg API) to 0.876 g/cm3 (30 deg API). Cumulative peak gas production was 21100000 Sm3/day. Average gas gravity with respect to air was 0.65. Condensate produced in conjunction with the gas tests totalled 185 standard cubic meters per day (1166 BCPD) with an average gravity of 0.75 g/cm3(57 API). The average temperatures measured at the gauge carriers were: 83.4 (DST 1), 82.8 (DST 2), 80.9 (DST 3), 80.8 (DST 4A), 77.2 (DST 5), 72.4 (DST 6), and 75.5 (DST 7). -
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]480.003262.20 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom12283.52295.7[m ]22300.52310.7[m ]32316.02318.5[m ]42320.02325.1[m ]52327.02342.0[m ]62345.02362.0[m ]72363.52378.1[m ]82379.02392.0[m ]92394.02408.6[m ]102410.02420.1[m ]112422.02427.2[m ]122431.02435.0[m ]132436.02443.5[m ]142444.02448.2[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]135.2Cores 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 availableDST2417.002439.0029.04.1985 - 00:00YESDSTDST22365.002376.0030.04.1985 - 00:00YESDSTDST4A2330.002340.0024.05.1985 - 00:00YESDSTDST52290.002310.0029.05.1985 - 00:00YESDSTDST62232.002245.0001.06.1985 - 00:00YESDSTDST72203.002222.0005.06.1985 - 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 typeCONDUCTOR30474.036476.00.00LOTSURF.COND.201025.8261030.01.52LOTINTERM.13 3/82100.017 1/22110.01.76LOTINTERM.9 5/82599.712 1/42610.01.81LOTINTERM.9 5/82600.212 1/42610.01.81LOTOPEN HOLE3262.08 1/23262.00.00LOT -
Drill stem tests (DST)
Drill stem tests (DST) Test numberFrom depth MD
[m]To depth MD
[m]Choke size
[mm]1.0252125296.12.02417243925.42.1241724399.52.2241724399.52.32417243925.43.02357237625.44.02330234022.25.02290231019.16.02232224519.17.02203222220.2Drill stem tests (DST) Test numberFinal shut-in pressure
[MPa]Final flow pressure
[MPa]Bottom hole pressure
[MPa]Downhole temperature
[°C]1.01.00026.0002.02.15.0002.25.0002.36.0003.00025.0003.040.0004.04.00025.0005.012.0006.05.0007.09.000Drill stem tests (DST) Test numberOil
[Sm3/day]Gas
[Sm3/day]Oil density
[g/cm3]Gas grav. rel.airGOR
[m3/m3]1.02.0704340000.9220.617482.1208120000.910572.2208120000.910572.3704340000.920493.0489320000.9820.668654.0902680000.8760.660755.0737240000.7540.65099656.017450000.7550.65026327.0969000000.7559360 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CBL VDL GR CCL19002597CST19402097CST21152591CST26103249DLL MSFL GR SP21002602ISF BHC MSFL GR SP4741028ISF LSS MSFL GR SP10262109ISF LSS MSFL GR SP21002605ISF LSS MSFL GR SP26023250LDT CNL GR20162110LDT CNL GR26023250LDT CNL NGS21002606MWD - GYRO MULTISHOT4743262RFT22052574SHDT GR10262110SHDT GR21002606SHDT GR26023250TEMP5002025TEMP9982551VSP4743250 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit376376145418631863194419441977204222032217221722852482 -
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]pdf20.53pdf2.39 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured3830.00WATER BASED25.02.19854261.02180.0WATER BASED27.02.19854761.06180.0WATER BASED27.02.19854761.02180.0WATER BASED01.03.19854761.02180.0WATER BASED01.03.19858361.125.077.0WATER BASED03.03.198510301.126.0148.0WATER BASED03.03.198510301.027.0115.0WATER BASED03.03.198510301.269.0124.5WATER BASED04.03.198510301.027.0115.0WATER BASED03.03.198510301.269.0124.5WATER BASED04.03.198510701.0823.076.6WATER BASED10.03.198514861.3521.057.5WATER BASED10.03.198516461.3911.086.2WATER BASED11.03.198518621.4311.091.0WATER BASED12.03.198520521.4514.0115.0WATER BASED13.03.198521101.4814.0124.0WATER BASED14.03.198521101.4714.0110.0WATER BASED17.03.198521101.4714.0110.0WATER BASED17.03.198521791.5414.0119.7WATER BASED19.03.198522281.5614.081.3WATER BASED20.03.198522841.5816.095.7WATER BASED21.03.198523131.5816.095.7WATER BASED24.03.198523271.5816.095.7WATER BASED24.03.198524031.5816.095.8WATER BASED27.03.198524361.5816.065.6WATER BASED29.03.198525821.5816.0105.3WATER BASED01.04.198526051.5818.081.4WATER BASED01.04.198526101.5822.071.8WATER BASED09.04.198526101.5823.081.4WATER BASED09.04.198526101.5820.067.0WATER BASED09.04.198526101.5823.086.2WATER BASED09.04.198526101.5823.081.4WATER BASED09.04.198526101.5820.067.0WATER BASED09.04.198526101.5823.086.2WATER BASED09.04.198526271.5013.067.0WATER BASED09.04.198526451.4815.062.2WATER BASED09.04.198526801.4415.062.3WATER BASED10.04.198527281.4216.071.8WATER BASED11.04.198528101.3915.071.8WATER BASED12.04.198529171.3917.062.2WATER BASED15.04.198529891.3915.067.0WATER BASED15.04.198531351.3916.067.0WATER BASED15.04.198532621.3916.076.6WATER BASED16.04.198532621.3916.076.6WATER BASED17.04.198532621.3920.095.6WATER BASED18.04.198532621.3920.095.6WATER BASED18.04.198532621.3916.076.6WATER BASED17.04.1985 -
Palynological slides at the Norwegian Offshore Directorate
Palynological slides at the Norwegian Offshore Directorate Sample depthDepth unitSample typeLaboratory2000.0[m]DCOD2021.0[m]DCOD2042.0[m]DCOD2060.0[m]DCOD2081.0[m]DCOD2099.0[m]DCOD2108.0[m]DCOD2120.0[m]DCOD2129.0[m]DCOD2141.0[m]DCOD2150.0[m]DCOD2162.0[m]DCOD2171.0[m]DCOD2180.0[m]DCOD2192.0[m]DCOD2199.0[m]DCOD2210.0[m]DCOD2219.0[m]DCOD2231.0[m]DCOD2243.0[m]DCOD2249.0[m]DCOD2261.0[m]DCOD2273.0[m]DCOD2282.0[m]DCOD2294.0[m]DCOD2318.0[m]DCOD2330.0[m]DCOD2345.0[m]DCOD2363.0[m]DCOD2381.0[m]DCOD2405.0[m]DCOD2426.0[m]DCOD2435.0[m]DCOD2444.0[m]DCOD2450.0[m]DCOD2462.0[m]DCOD2474.0[m]DCOD2486.0[m]DCOD2495.0[m]DCOD2528.0[m]DCOD2555.0[m]DCOD2585.0[m]DCOD2615.0[m]DCOD2645.0[m]DCOD2675.0[m]DCOD2705.0[m]DCOD2735.0[m]DCOD2765.0[m]DCOD2795.0[m]DCOD2825.0[m]DCOD2855.0[m]DCOD2885.0[m]DCOD2915.0[m]DCOD2945.0[m]DCOD2975.0[m]DCOD2999.0[m]DCOD