34/7-5
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General information
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Wellbore history
GeneralWell 34/7-5 is located in the Statfjord Øst area of the Northern North Sea. The primary objectives of the well were to test the reservoir potential of the Brent Group, and to determine if the oil/water contact is the same as that found in the 33/9-7 Statfjord Øst discovery well drilled to the south southwest of this well in the neighbouring block, but on the assumed same structure. A secondary objective was to test the reservoir potential of the Statfjord Formation.Operations and resultsWildcat well 34/7-5 was spudded with the semi-submersible installation Treasure Saga on 17 January 1985 and drilled to TD at 3146 m in the Late Triassic Lunde Formation. Drilling proceeded without significant problems. The well was drilled with spud mud down to 930 m and with gypsum/polymer mud from 930 m to TD.Trace oil shows appeared in sandstone lamina in the Cretaceous from about 2380, limestones had shows from about 2488 m. The Brent Group reservoir came in at 2502 m, approximately 60 m deeper than prognosed. Hydrocarbons were encountered in the upper section belonging to the Ness Formation. The oil/water contact could not be defined from pressure data. From shows on cores and the well logs an OWC could be placed at approximately 2521 m, in accordance with the results from well 33/9-7. Below the OWC oil shows on sandstone decreased gradually from 2523 m until they vanished at 2616 m. The Statfjord Formation was dry.Eleven cores were cut. Cores 1 to 10 were cut from 2508 m to 2633 m in the Brent Group and the uppermost part of the Drake Formation. Core 1, from 2508 to 2510 gave no recovery. The core depths for Cores 2 to 10 were from 0.5 m to 2.2 m short of logger's depth. Core 11 was cut from 2869 m to 2883.5 m in the calcareous Amundsen Formation. For this core there was no difference between core depth and logger's depth. No wire line fluid samples were taken.The well was permanently abandoned on 16 March 1985 as an oil appraisal.TestingTwo drill stem tests were performed from the interval 2502.5 - 2512.5 m.The first test, DST 1, produced oil with a water cut of 50%, strongly suggesting water channelling behind casing from the underlying water zone.Cement was squeezed behind casing to isolate the perforated zone and a second repeat test, DST 1A was initiated. This test produced clean oil at a rate of 260 Sm3 /day through a 9.5 mm choke. The wellhead pressure was 72 bar. The highest recorded bottom hole temperature was 88 deg C in both DST 1 and in DST 1A. -
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]390.003147.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom22510.02520.7[m ]32521.02527.3[m ]42529.52541.2[m ]52542.02555.1[m ]62555.12571.9[m ]72573.02590.7[m ]82591.02607.5[m ]92609.02622.2[m ]102624.02631.6[m ]112869.02883.4[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]127.7Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
Core photos
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Palynological slides at the Norwegian Offshore Directorate
Palynological slides at the Norwegian Offshore Directorate Sample depthDepth unitSample typeLaboratory2148.0[m]DCRRI2166.0[m]DCRRI2196.0[m]DCRRI2211.0[m]DCRRI2241.0[m]DCRRI2256.0[m]DCRRI2271.0[m]DCRRI2320.0[m]DCRRI2510.5[m]CRRI2535.0[m]DCRRI2556.0[m]DCRRI2565.0[m]DCRRI2577.0[m]DCRRI2598.0[m]DCRRI2610.0[m]DCRRI2621.4[m]CRRI2624.3[m]CRRI2626.0[m]CRRI2628.7[m]CRRI2631.3[m]CRRI2709.0[m]DCRRI2727.0[m]DCRRI2739.0[m]DCRRI2781.0[m]DCRRI2796.0[m]DCRRI2811.0[m]DCRRI2826.0[m]DCRRI2895.0[m]DCRRI2910.0[m]DCRRI -
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 availableDSTDST1A2502.502512.5008.03.1985 - 01:00YES -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit270107510821094123913301670167017381841188519111911209024852485248924962496250225022531256426222622269627682794289330103010 -
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]pdf1.94pdf41.54 -
Drill stem tests (DST)
Drill stem tests (DST) Test numberFrom depth MD
[m]To depth MD
[m]Choke size
[mm]1.0250325129.52.0250225129.5Drill stem tests (DST) Test numberFinal shut-in pressure
[MPa]Final flow pressure
[MPa]Bottom hole pressure
[MPa]Downhole temperature
[°C]1.013.0009.00036.0002.011.000Drill stem tests (DST) Test numberOil
[Sm3/day]Gas
[Sm3/day]Oil density
[g/cm3]Gas grav. rel.airGOR
[m3/m3]1.0318460000.0850.7601452.026240000.845151 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]ACBL6801840CDL CNL GR18432746CDL CNL GR24703143CDL GR379929CDL GR9121860DIFL LSBHC GR379929DIFL LSBHC GR9121863DIFL LSBHC GR18403143DIPLOG18403143DLL MLL GR24502746FMT18403143FMT18432746GR120384SIGNATURE24402610SIGNATURE28913115SWC00VSP3803131 -
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 typeCONDUCTOR30380.036790.00.00LOTSURF.COND.20913.026930.01.52LOTINTERM.13 3/81844.017 1/21865.01.79LOTINTERM.9 5/82636.012 1/43146.00.00LOT -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured3841.03WATER BASED18.01.19857901.10WATER BASED25.01.19859301.12WATER BASED25.01.198511641.1010.017.0WATER BASED29.01.198514891.2210.013.0WATER BASED29.01.198517851.4020.022.0WATER BASED29.01.198518651.4319.018.0WATER BASED29.01.198518651.4350.018.0WATER BASED29.01.198518651.4350.018.0WATER BASED29.01.198519851.5255.018.0WATER BASED31.01.198521381.6255.016.0WATER BASED01.02.198523251.6655.020.0WATER BASED04.02.198524341.6950.015.0WATER BASED04.02.198524541.6952.015.0WATER BASED04.02.198526721.6855.016.0WATER BASED12.02.198527501.6864.017.0WATER BASED13.02.198527501.6854.013.0WATER BASED14.02.198527501.6854.013.0WATER BASED14.02.198527941.6351.018.0WATER BASED15.02.198528361.6451.018.0WATER BASED18.02.1985 -
Pressure plots
Pressure plots The pore pressure data is sourced from well logs if no other source is specified. In some wells where pore pressure logs do not exist, information from Drill stem tests and kicks have been used. The data has been reported to the NPD, and further processed and quality controlled by IHS Markit.Pressure plots Document nameDocument formatDocument size [MB]pdf0.22