34/8-8 R
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General information
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Wellbore history
GeneralWell 34/8-8 R is a re-entry of appraisal well 34/8-8 on the N-1 segment of the 34/8-1 Visund discovery on Tampen Spur in the Northern North Sea. The primary objective of well 34/8-8R was to determine the pressure regime and pressure gradient in the hydrocarbon bearing sands in Tarbert, Ness and Etive formations. The secondary objective was to determine the fluid system/composition and the possible presence of a gas oil contact in the Tarbert/Ness formations. The third objective was to investigate the mobility of oil and water down to the interpreted free water level (FWL)Operations and resultsWell 34/8-8 was re-entered on 16 February 1993 with the semi-submersible installation Polar Pioneer.The well was drill stem tested. No significant problems occurred in the operations.No cores were cut and no wire line fluid samples were taken.The well was permanently abandoned on 9 March 1993 as an oil appraisal.TestingTwo drill stem tests were performed. In both tests production logging (PLT) was performed during the main flow.DST 1 tested the interval 2960.2 to 2973.2 m in the Ness/Etive formations. The test sequence consisted of an initial and a cleanup flow/build-up period with down hole shut-in. The main flow with PLT was interrupted by poor weather conditions and the well was immediately killed. Only a limited amount of the surface sampling program was therefore accomplished. No down hole samples were collected. The test produced 775 Sm3 oil, 10600 Sm3 gas and 161 m3 water/day through a 12.7 mm choke in the cleanup flow. GOR was 137 Sm3/Sm3. The oil density was 0.852 g/cm3 and the gas gravity was 0.665 (air = 1) with 1.6% CO2 and 0.25 ppm H2S. Flowing BHP was 423.3 bar and flowing BHT was 112.3 deg C. The PLT results showed an effective OWC at 2971.5.DST 2 tested the interval 2921 to 2950 in the Tarbert/Ness formations. The test sequence consisted of an initial and a cleanup flow/build-up period with down hole shut-in. After the cleanup build-up bottom hole sampling was accomplished with the well flowing on a low rate. Three out of five samples were good. The well was production logged (PLT) during the dual rate main flow period. The test produced 956 - 772 Sm3 oil, 147100 Sm3 gas and 0 m3 water/day through a 19.05 mm choke in the main flow. GOR was 164 - 191 Sm3/Sm3. The oil rate was steadily decreasing while the gas rate was relatively constant. Consequently, the GOR steadily increased during this period. The oil density was 0.844 g/cm3 and the gas gravity was 0.660 (air = 1) with 1.4% CO2 and 1.5 ppm H2S. Flowing BHP was 234.6 bar and flowing BHT was 112.4 deg C. No gas/oil contact was reported from the test.After the main build-up with surface shut-in, a minifracture test was performed. -
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 availableDSTTEST12973.202960.2021.02.1993 - 12:45YESDSTTEST22950.002921.0026.02.1993 - 13:25YES -
Drill stem tests (DST)
Drill stem tests (DST) Test numberFrom depth MD
[m]To depth MD
[m]Choke size
[mm]1.02960297312.72.02921295019.0Drill stem tests (DST) Test numberFinal shut-in pressure
[MPa]Final flow pressure
[MPa]Bottom hole pressure
[MPa]Downhole temperature
[°C]1.020.00042.0001122.08.00023.000112Drill stem tests (DST) Test numberOil
[Sm3/day]Gas
[Sm3/day]Oil density
[g/cm3]Gas grav. rel.airGOR
[m3/m3]1.07751063000.8520.6651372.09561471000.8440.660164 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]BHS PLT29152955CBL VDL GR CCL26003106CCL29212950CCL29863108GR CCL27732828GR CCL28002870GR CCL28002870LDL CNL GR27643282PLT29152955PLT29552985 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit36411151164119013681401152715591829182918731998199822312877287728832900290029022921292129352967300730773077312232603286338734743474 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured10001.4712.09.0WATER BASED08.03.199310001.4712.09.0WATER BASED10.03.199310001.4712.09.0WATER BASED09.03.199327271.4712.010.0WATER BASED08.03.199328771.6315.014.0WATER BASED01.03.199328771.6315.014.0WATER BASED01.03.199328771.6315.014.0WATER BASED01.03.199328771.6315.014.0WATER BASED02.03.199328771.6315.014.0WATER BASED03.03.199328941.6315.015.0WATER BASED08.03.199329091.6320.015.0WATER BASED23.02.199329091.6315.015.0WATER BASED23.02.199329091.6317.015.0WATER BASED23.02.199329091.6314.014.0WATER BASED24.02.199329571.6315.015.0WATER BASED24.02.199329571.6315.014.0WATER BASED26.02.199329571.6314.014.0WATER BASED04.03.199329571.6314.013.0WATER BASED08.03.199329571.6314.013.0WATER BASED08.03.199329571.6315.014.0WATER BASED26.02.199331111.6319.019.5WATER BASED18.02.199331111.6320.015.0WATER BASED18.02.199331111.6319.017.0WATER BASED19.02.1993