1/9-6 S
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General information
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Wellbore history
GeneralWell 1/9-6 S was drilled on the north-west flank of the Tommeliten Gamma structure in the Feda Graben in the southern North Sea. The main objective was to appraise the Tommeliten Field. The well was drilled deviated due to the planned use of this well as a production well. The main targets were the Ekofisk and Tor formations.Operations and resultsAppraisal well 1/9-6 was spudded with the semi-submersible installation Sedco 703 on 21 March 1982. Drilling of the 36" and 26" holes went without incident. There was some difficulty in getting logging tools in the 17 1/2" hole. Gumbo problems occurred while drilling the 12 1/4" hole and both open hole and cased hole logging runs were plagued with tool failures. Differential sticking also occurred while drilling the bottom part of the 8 1/2" hole. TD was set 3880 m, 99 m into the Late Cretaceous Hod Formation. After retrieving the RFT the well began flowing and sloughing large amounts of shale below the 9 5/8" shoe. While circulating and reaming to TD, the pipe became stuck many times due to shale sloughing above the bit. A bit and bit sub were left in the hole during these hole problems, and were never recovered. The well was drilled with "native" mud/seawater down to 1471 m and with polymer/dispersed solids/lignosulphonate/seawater from 1471 m to TD.Top Ekofisk Formation was penetrated at 3411 m (3110 m TVD) and top Tor Formation at 3516 m (3199 m TVD). Both formations were gas/condensate bearing. No other permeable section in the well had indications of hydrocarbons.A total of 14 cores were cut in the interval 3415.7 - 3619 m in the Ekofisk and Tor formations. Problems with jamming and differential sticking occurred while coring. The overall recovery was 90%. One run with the RFT tool on wire line was conducted, taking 14 good pressure points, but no fluid sample due to tight formation and stuck tool.After testing the well was suspended on 1 December as a possible future producer. It is classified as a gas/condensate appraisal well.TestingFour DST's were performed in this well. Technical and operational problems plagued all tests.DST1 tested the interval 3771.6 - 3776.8 m (3424.0 - 3428.6 m TVD) in the water zone at base Tor Formation. A few m3 water was produced in each of several flow periods. The temperature recorded in DST 1, at measurement depth 3750.4 m varied between 130.7 deg C and 133.0 deg C for different periods and gauges, with 131.7 deg C taken as a representative temperature.DST 2, 2A, and 2B tested the interval 3636.3 - 3654.6 m (3301.0 - 3316.7 m TVD) in the lower Tor Formation. The first test, DST 2, was aborted due to technical problems. Maximum rate achieved from DST 2A was 536604 Sm3 /day of gas and 477 Sm3 /day of condensate on 32/64" choke. GOR was 1125 Sm3/Sm3, oil density was 0.810, and gas gravity was 0.689 (air = 1). H2S was measured to be 4-6 ppm and the CO2 content was measured to be 3%. This test was aborted when the tester valve cut the wire line, and the zone was retested as DST 2B. The maximum flow rates were then close to 700 x 10 Sm3 /day of gas and 500 - 550 Sm3 /day of condensate on a 28/64". The maximum temperature in different flows from this interval, measured at 3652 m, varied between 121.8 and 122.4 deg CDST 3 tested the intervals 3587.5 - 3578.4 m, 3569.2 - 3560.1 m and 3550.9 - 3523.5 m in the Tor Formation. It flowed 243808 Sm3 gas and 231 Sm3 condensate/day on a 16/64" choke after acidizing. GOR was 1054 Sm3/Sm3, condensate density was 0.823 g/cm3 and gas gravity was 0.680 (air = 1). Final build-up period was terminated mid-way due to technical problems. Same interval was tested in DST3A without further acidizing. This test produced 241259 Sm3 gas and 202 Sm3 condensate/day on a 20/64" choke. The GOR was 1196 Sm3/Sm3, the oil density was 0.791 g/cm3 and gas gravity was 0.684 (air = 1). The temperature measured at 3522.6 m was 131.1 deg CDST 4 was perforated in two intervals, the upper zone from 3416.8 - 3426.0 m (3114.8 - 3122.7 m TVD) and the second from 3444.2 - 3459.4 m (3138.2 - 3151.3 m TVD), both in the Ekofisk formation. It produced gas and condensate after stimulation. The maximum rates from these intervals were 834213 Sm3 gas and approximately 559 Sm3 condensate/day of condensate on a 56/64" choke. The GOR was 1491 Sm3/Sm3 on this choke. A GOR of 2800 Sm3/Sm3 was measured before acidization, with a low flowing pressure. -
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]170.003880.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom13415.73426.3[m ]23427.03444.4[m ]33445.03457.0[m ]43463.63481.1[m ]53481.73499.5[m ]63500.93517.8[m ]73518.73530.0[m ]83530.53534.3[m ]93537.93555.0[m ]103556.53573.5[m ]113575.03584.4[m ]123584.83597.5[m ]133598.03615.8[m ]143618.13618.7[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]182.0Cores 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 availableDSTTEST2A3636.003655.0017.09.1982 - 00:00YESDSTTEST2B3655.003636.0017.09.1982 - 00:00YESDSTTEST33523.003587.0003.10.1982 - 00:00YESDSTTEST43417.003459.0025.11.1982 - 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 typeCONDUCTOR30168.036168.00.00LOTSURF.COND.20463.026479.01.34LOTINTERM.13 3/81453.017 1/21472.01.87LOTINTERM.9 5/83140.012 1/43155.02.06LOTLINER73866.08 1/23880.00.00LOT -
Drill stem tests (DST)
Drill stem tests (DST) Test numberFrom depth MD
[m]To depth MD
[m]Choke size
[mm]1.0377237770.02.03636365511.13.03524358817.44.03417345922.2Drill stem tests (DST) Test numberFinal shut-in pressure
[MPa]Final flow pressure
[MPa]Bottom hole pressure
[MPa]Downhole temperature
[°C]1.02.03.04.0Drill stem tests (DST) Test numberOil
[Sm3/day]Gas
[Sm3/day]Oil density
[g/cm3]Gas grav. rel.airGOR
[m3/m3]1.02.05005300000.7990.70511153.07008500000.8280.68712154.06058500000.8780.6951406 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CBL4351452CNL11001500COMPARISON FDC GR31393877DLL MSFL GR31393876EPT PDC GR31393877ISF BHC GR SP4623154ISF BHC NGT SP29803877ISF SON GR SP100478LDL GR4621223LDL GR14513153LDT CNL31393877NGT29803867OH VAVEFORM31393867OH VDL31393867PEQ34003800RFT31393880SHDT31393880 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit1021755324232423275332234003411341135163781 -
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]pdf2.63pdf0.71pdf3.98pdf0.07pdf0.05pdf0.06pdf0.05pdf47.50pdf2.77pdf2.96pdf0.11pdf0.09pdf0.03pdf0.46pdf3.85pdf1.95pdf1.22pdf2.56pdf2.79pdf2.60pdf0.25pdf5.86pdf2.70pdf1.90pdf1.39pdf0.88pdf0.41pdf0.61pdf1.08pdf1.11pdf1.10pdf0.33pdf11.68pdf4.85pdf2.59pdf0.33pdf0.39pdf0.65pdf6.62pdf3.18pdf6.06pdf3.77pdf2.33pdf6.49pdf10.47pdf0.20pdf0.14 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured1631.05spud mud4781.02spud mud7011.08waterbased14711.31waterbased14711.33waterbased17291.70waterbased28691.87waterbased31551.87waterbased33591.70waterbased34141.65waterbased35371.58waterbased35741.57waterbased38791.59waterbased