General information Attribute Value Wellbore nameOfficial name of wellbore based on NPD guidelines for designation of wells and wellbores.25/4-6 S TypeWellbore type. Legal values: EXPLORATION, DEVELOPMENT, OTHER (see 'Purpose' for more information)EXPLORATION PurposeFinal classification of the wellbore.
Legal values for exploration wellbores:
WILDCAT, APPRAISAL, WILDCAT-CCS, APPRAISAL-CCS.
Legal values for development wellbores:
OBSERVATION, PRODUCTION, INJECTION, INJECTION-CCS, OBSERVATION-CCS.
Legal values for other wellbores:
SOIL DRILLING (drilling in connection with track surveys and other subsurface surveys to investigate the soil conditions prior to placement of facilities),
SHALLOW GAS (drilling to investigate shallow gas before the first 'real' drilling on the location),
PILOT (drilling to investigate the geology and fluid connectors for location of the main wellbore),
SCIENTIFIC (drilling according to Law of Scientific research and exploration),
STRATIGRAPHIC (driling according to Law of Petroleum activities §2-1).WILDCAT
StatusStatus for the wellbore. Legal values are:
BLOWOUT: A blowout has occurred in the well.
CLOSED: A development wellbore that has been closed in a shorter or longer periode. Also applies to development wellbores where drilling is completed, but production/injection has not yet been reported.
DRILLING: The well is in the drilling phase - can be active drilling, logging, testing or plugging,
JUNKED: The drilling operation has been terminated due to technical problems.
P&A: Exploration: The well is plugged and abandoned, and can not be reentered for further use. Development wells: The production/injection from/to the well is stopped and the well is plugged. The wellhead is removed or else made unavailable for further well operations.
PLUGGED: The wellbore has been plugged, but the upper parts of the wellbore can be re-used. A sidetrack might be drilled at a later stage.
PRODUCING: It was produced from the wellbore at the time of the operators last monthly report to the NPD.
INJECTING: It was injected to the wellbore at the time of the operators last monthly report to the NPD.
PREDRILLED: The upper part of the well has been drilled, usually as part of a batch-drilling campaign covering several wellbores.
RE-CLASS TO DEV: Exploration wellbore that is reclassified to a development wellbore.
RE-CLASS TO TEST: Exploration wellbore that is reclassified to test production.
SUSPENDED: The drilling operation in the wellbore has been temporarily stopped. The current plan is to continue drilling later on.
SUSPENDEDFactmaps in new window
Main areaName of the area on the Norwegian Continental Shelf where the wellbore is located. Legal values: BARENTS SEA, NORWEGIAN SEA, NORTH SEA.NORTH SEA FieldName of the field the wellbore is related to. DiscoveryName of the discovery the wellbore is related to. Well nameOfficial name of the parent well for the wellbore based on NPD guidelines for designation of wells and wellbores.25/4-6 Seismic locationPosition of spud location on seismic survey lines. SP: shotpoint.EL8802 - 110 SP 205 Production licenceOfficial designation of the production licence the wellbore was drilled or planned to be drilled from ( well head posistion). Drilling operatorName of the licensee starting the drilling operation on behalf of the active production license (well head position). This will usually equal the operator of the production license.Elf Petroleum Norge AS Drill permitThe drilling permit number together with the version of the drilling permit as stated in the drilling permit granted by the NPD.678-L Drilling facilityNPD's name of the facility which the wellbore was drilled from. Drilling daysNumber of days from wellbore entry to wellbore completion.132 Entered dateThe date when he wellbore was spudded. For sidetracks: The date when new formation was drilled by kicking off from the mother-wellbore,15.04.1991 Completed dateExploration wellbores from moveable facilities:
For floating facilities - date when anchor handling is started. For jackups - date the jacking-down started. Exploration wellbores from fixed facilities and all development wellbores:
Date when the wellbore is at total depth, and last casing, liner or screen is set. In case of immediate plugging of the wellbore, completed date equals the date the last plug i set in the wellbore.
Date when the wellbore is at total depth, and last casing, liner or screen is set. In case of immediate plugging of the wellbore, completed date equals the date the last plug i set in the wellbore.
Release dateDate when raw data which has been reported to the authorities from the wellbore is not confidential any longer. Normally 2 years after finishing the drilling. May be earlier if the area of the production license is relinquished.24.08.1993 Publication dateDate quality control of the wellbore information was completed, so it can be published on the internet as a 'Well Data Summary Sheet' wellbore with more information available than other wellbores.15.02.2006 Purpose - plannedPre-drill purpose of the wellbore. Legal values for exploration wellbores: WILDCAT, APPRAISAL, WILDCAT-CCS, APPRAISAL-CCS. Example of legal values for development wellbores: OBSERVATION, PRODUCTION, INJECTION.WILDCAT ReentryStatus whether the wellbore has been re-entered (YES) or not (NO). Re-entered wellbores are not included in the count when wellbores are presented in statistical overviews.NO ContentFor exploration wellbores, status of discovery.
DRY, SHOWS (trace amounts of hydrocarbons), GAS, GAS/CONDENSATE, OIL or OIL/GAS.
SHOWS (GAS SHOWS, OIL SHOWS or OIL/GAS SHOWS) are detected as fluorescent cut (organic extract), petroleum odour, or visual stain on cuttings or cores, or as increased gas reading on the mud-loggers gas detection equipment.
Legal values for WILDCAT-CCS and APPRAISAL-CCS: WATER
For development wellbores, type of produced/injected fluid.
WATER, CUTTINGS, NOT AVAILABLE, OIL, GAS/CONDENSATE, OIL/GAS, CO2, GAS, WATER/GAS, NOT APPLICABLE.GAS/CONDENSATE
Discovery wellboreIndicator which tells if the wellbore made a new discovery. Legal values: YES, NO. Prior to press-release or other information regarding drilling results, the indicator will be “NO” as a default.YES 1st level with HC, ageAge of lithostratigraphic unit, 1st level, where hydrocarbons were encountered. Examples of legal values: CRETACEOUS, EARLY CRETACEOUS, LATE JURASSIC, EOCENE. See also NPD bulletins.MIDDLE JURASSIC 1st level with HC, formationName of lithostartigraphic unit, 1st level, where hydrocarbons were encountered. Shown only for released wells. Examples of legal values: BASEMENT, COOK FM, EKOFISK FM, HEIMDAL FM, SANDNES FM, SOGNEFJORD FM, TARBERT FM, BRENT GP. See also NPD bulletins.HUGIN FM Kelly bushing elevation [m]Elevation of the rotary kelly bushing (RKB) above mean sea level.22.0 Water depth [m]Depth in metres betweem mean sea level and sea floor.114.0 Total depth (MD) [m RKB]Total measured length of wellbore from kelly bushing to total depth (driller's depth).4170.0 Final vertical depth (TVD) [m RKB]Vertical elevation from total depth to kelly bushing. Shown only for released wells. Referred to as true vertical depth (TVD).4136.0 Maximum inclination [°]Maximum deviation, in degrees, from a vertical well path.Shown only for released wells.22.5 Bottom hole temperature [°C]Estimated temperature at final total depth of the wellbore. Shown only for released wells. See discription.143 Oldest penetrated ageAge (according to Geologic Time Scale 2004 by F. M. Gradstein, et al. (2004)) of the oldest penetrated formation. May differ from age at TD for example in deviated wellbores. Examples of legal values: CRETACEOUS, EARLY CRETACEOUS, LATE JURASSIC, EARLY PERMIAN, EARLY TRIASSIC, EOCENE.EARLY JURASSIC Oldest penetrated formationName of the oldest lithostratigraphic unit penetrated by the wellbore. Shown only for released wells. In most wellbores this is formation or group at total depth. May differ from formation or group at TD for example in wellbores drilled with high deviation or through faults. Examples of legal values: AMUNDSEN FM, BALDER FM, BASEMENT, BLODØKS FM, BRYNE FM, BURTON FM, COOK FM, DRAKE FM, DRAUPNE FM, EKOFISK FM, DUNLIN GP.STATFJORD GP Geodetic datumReference system for coordinates. Example of legal values: ED50.ED50 NS degreesGeographic coordinate of the wellhead, north-south degrees.59° 42' 35.43'' N EW degreesGeographic coordinate of the wellhead, east-west degrees.2° 19' 4.45'' E NS UTM [m]Universal Transverse Mercator coordinate of the wellhead, north-south.6619449.04 EW UTM [m]Universal Transverse Mercator coordinate of the wellhead, east-west.461620.07 UTM zoneUniversal Transverse Mercator zone. Examples of legal values: 31, 32, 33, 34.31 NPDID wellboreNPD's unique id for the wellbore.1703
Wellbore historyGeneralWell 25/4-6 S was planned to prove the hydrocarbon potential in a structure located on the northern extension of the Heimdal Ridge. The structure is located in the NE corner of block 25/4, fairly close to the Heimdal, Frøy and Frigg Fields. Four-ways closures were mapped on all levels from the "Near top Frigg sequence" marker to the Base Vestland Group Marker. The structure above the Base Cretaceous Unconformity is a fairly simple dome/mounded feature, while the Vestland Group and deeper sections consist of an antithetic tilted block. The objective of the well was to explore all closures down to at least Vestland Group level. The primary target was the Vestland Group; secondary targets were the Frigg and Heimdal Formations, while the Statfjord Formation was a third, optional target. Based on data from surrounding wells, no abnormal pressure was expected. To achieve an optimal position in reaching the targets the well was planned deviated.Operations and resultsWildcat well 25/4-6 S was spudded with the semi-submersible installation West Vanguard on 15 April 1991 and drilled to TD at 4170 m, 41 m into the Statfjord Formation. The well was drilled vertical (max 2 deg deviation) through the Frigg and Heimdal prospects down to 2424 m. From here angle was built up to a maximum of 22.5 deg at 3025 m before it was dropped off again to 3 deg at final TD. The hole opener cone was lost at 266 m resulting in 8 days and 15 hours lost time before drilling could be resumed. The FMT tool got stuck at 3836 m with fishing unsuccessful. Thus it was decided to set a cement plug on top of the tool and perform a sidetrack. The well was drilled with seawater and viscous pills down to 197 m, with bentonite mud from 197 m to 1220 m, with KCl/polymer mud from 1220 m to 2503 m, and with lignosulphonate mud from 2503 m to TD.The Early Eocene Frigg reservoir was not found, and the Palaeocene Heimdal reservoir was water bearing. Top Vestland Group came in at a depth of 3716 m, 37 m deeper than predicted. The group was 222 m thick and hydrocarbon bearing over the uppermost 120 m (hydrocarbon/water contact at 3836 m). The reservoir fluid type was assumed to be a condensate/wet gas with a 0.486 g/cc gradient over the HC-bearing zone, according to the RFT measurements. The Statfjord Formation was water bearing.A total of 12 conventional cores were cut from the Vestland Group, Dunlin Group, and the Statfjord Formation. The mismatch between core depth and logger's depth was large. Core depth had to be added a correction of 8.5 m to 11 m in order to match with the logger's depth. A total of 25 sidewall cores were attempted and 19 were recovered. Two FMT fluid samples were taken, at 3803.5 m in the Hugin Formation and at 4141.5 m in the Statfjord Formation. Both recovered salt water with a small volume of gas.The well was suspended on 24 August 1991 as a gas/condensate discovery.TestingOne DST tests was performed in the interval 3802-3819 m and flowed at a rate of 461700 Sm3/d gas and 688 Sm3/d oil through a 20.64 mm choke. The GOR was 671 Sm3/Sm3 with an oil density of 0.82 g/ml (41 deg API).
Cuttings at the NPD
Cuttings at the NPDCuttings available for sampling?YES Cuttings at the NPDCutting sample, top depth [m]Cutting samples, bottom depth [m]210.004020.00
Cores at the NPD
Cores at the NPDCore sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom13712.03714.3[m ]23715.03733.2[m ]33734.03745.8[m ]43746.03774.0[m ]53774.03790.4[m ]63791.03818.8[m ]73819.03846.3[m ]83846.53873.0[m ]93874.03902.2[m ]104061.04070.0[m ]114124.04131.1[m ]124131.54134.0[m ] Cores at the NPDTotal core sample length [m]205.0 Cores at the NPDCores available for sampling?YES
Palynological slides at the NPD
Palynological slides at the NPDSample depthDepth unitSample typeLaboratory2100.0[m]DCPETROSTR2110.0[m]DCPETROS2120.0[m]DCPETROS2130.0[m]DCPETROS2140.0[m]DCPETROS2150.0[m]DCPETROS2160.0[m]DCPETROS2170.0[m]DCPETROS2180.0[m]DCPETROS2190.0[m]DCPETROS2200.0[m]DCPETROS2220.0[m]DCPETROS2240.0[m]DCPETROS2310.0[m]DCPETROS2330.0[m]DCPETROS2340.0[m]DCPETROS2360.0[m]DCPETROS2380.0[m]DCPETROS2390.0[m]DCPETROS2420.0[m]DCPETROS2440.0[m]DCPETROS2450.0[m]DCPETROS2460.0[m]DCPETROS2490.0[m]DCPETROS2510.0[m]DCPETROS2520.0[m]DCPETROS2530.0[m]DCPETROS2545.0[m]DCPETROS2555.0[m]DCPETROS2555.0[m]DCPETROS2570.0[m]DCPETROS2570.0[m]DCPETROS2580.0[m]DCPETROS2610.0[m]DCPETROS2620.0[m]DCPETROS2630.0[m]DCPETROS2650.0[m]DCPETROS2665.0[m]DCPETROS2685.0[m]DCPETROS2700.0[m]DCPETROS2715.0[m]DCPETROS2730.0[m]DCPETROS2740.0[m]DCPETROS2750.0[m]DCPETROS
Oil samples at the NPD
Oil samples at the NPDTest typeBottle numberTop depth
MD [m]Bottom depth
MD [m]Fluid typeTest timeSamples availableDSTDST13802.003819.0014.08.1991 - 00:00YES
LithostratigraphyTop depth [m]Lithostrat. unit1362259761192120312721362212121212136216922002611275927592903333533813485353235323545356335713571361937163716387439404129
Composite logsDocument nameDocument formatDocument size [MB]0.53
Geochemical informationDocument nameDocument formatDocument size [MB]5.25
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]4.69102.09
Drill stem tests (DST)
Drill stem tests (DST)Test numberFrom depth MD
[m]To depth MD
Drill stem tests (DST)Test numberFinal shut-in pressure
[MPa]Final flow pressure
[MPa]Bottom hole pressure
Drill stem tests (DST)Test numberOil
[g/cm3]Gas grav. rel.airGOR
LogsLog typeLog top depth [m]Log bottom depth [m]CAL1303430DIF AC GR40214140DIF AC GR CBL27064002DIFL AC ZDEN GR19102499DIFL AC ZDL GR24933591DIL SLS GR LDT CNL37004170DIP12072499DIP35953970DIP GR35813591DL GR40214170DLL MLL SL35784022FMT22052225FMT37363838MCL1503490MFC35853590MWD RWD1984022SBT GR CCL34304021SWC20372462VSP18004021ZDL CN GR35783878
Casing and leak–off tests
Casing and leak–off testsCasing typeCasing diam.
[m]LOT/FIT mud eqv.
[g/cm3]Formation test typeCONDUCTOR30197.036200.00.00LOTINTERM.201207.0261210.01.75LOTINTERM.13 3/82493.017 1/22495.01.84LOTINTERM.9 5/83578.012 1/43580.01.98LOTLINER74021.08 1/24170.02.15LOT
Drilling mudDepth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured3131.057.016.0WATER BASED22.04.19917171.088.022.0WATER BASED23.04.19919731.089.023.0WATER BASED24.04.199112151.099.019.0WATER BASED25.04.199112151.088.014.0WATER BASED26.04.199112151.097.020.0WATER BASED29.04.199112201.087.017.0WATER BASED29.04.199112201.09WATER BASED29.04.199112201.09WATER BASED30.04.199112201.09WATER BASED02.05.199112201.09WATER BASED03.05.199112201.09WATER BASED06.05.199112401.2520.014.0WATER BASED06.05.199112401.2525.036.0WATER BASED07.05.199115031.2521.032.0WATER BASED06.05.199120001.2528.018.0WATER BASED08.05.199120661.3029.019.0WATER BASED10.05.199123031.3031.019.0WATER BASED10.05.199124331.3030.019.5WATER BASED13.05.199124331.3029.016.0WATER BASED13.05.199124331.3029.016.0WATER BASED13.05.199124331.3526.014.5WATER BASED15.05.199124331.3825.012.5WATER BASED16.05.199124331.3824.014.0WATER BASED21.05.199124331.3822.014.5WATER BASED21.05.199124331.3823.029.0WATER BASED21.05.199124331.3825.015.0WATER BASED21.05.199124331.3826.015.5WATER BASED21.05.199124331.3522.017.0WATER BASED14.05.199124461.3823.014.5WATER BASED22.05.199125031.3821.014.0WATER BASED23.05.199125031.3824.012.0WATER BASED27.05.199125031.3823.011.5WATER BASED27.05.199125031.3823.011.5WATER BASED28.05.199125031.3823.012.0WATER BASED24.05.199125031.3823.024.0WATER BASED27.05.199125351.3629.015.0WATER BASED29.05.199126091.3633.013.0WATER BASED30.05.199126951.3628.033.0WATER BASED03.06.199126951.3625.017.5WATER BASED31.05.199127121.3626.031.0WATER BASED03.06.199127381.3624.013.5WATER BASED03.06.199127611.3626.012.0WATER BASED04.06.199127611.3626.012.0WATER BASED05.06.199127771.4228.014.0WATER BASED07.06.199127881.4228.014.0WATER BASED07.06.199128201.4231.028.0WATER BASED10.06.199128711.4231.013.5WATER BASED10.06.199130801.4232.025.0WATER BASED12.06.199131841.4232.013.5WATER BASED13.06.199133761.4228.010.0WATER BASED14.06.199134141.4222.019.0WATER BASED19.06.199134291.7545.012.0WATER BASED29.07.199134701.4224.020.0WATER BASED19.06.199135911.5628.017.0WATER BASED19.06.199135911.5627.017.0WATER BASED19.06.199135911.5625.05.7WATER BASED20.06.199135911.5625.07.5WATER BASED21.06.199135911.5727.010.5WATER BASED25.06.199135911.5727.08.1WATER BASED25.06.199135911.5630.022.0WATER BASED19.06.199135911.5621.07.5WATER BASED25.06.199135911.7523.08.6WATER BASED26.06.199136081.7523.09.6WATER BASED26.06.199136501.7531.010.1WATER BASED27.06.199137001.7531.012.0WATER BASED28.06.199137121.7528.010.5WATER BASED01.07.199137121.7525.09.6WATER BASED01.07.199137331.7528.09.6WATER BASED01.07.199137461.7529.09.6WATER BASED02.07.199137741.7528.09.5WATER BASED03.07.199137821.7529.010.5WATER BASED04.07.199138171.7532.010.5WATER BASED05.07.199138191.7531.09.6WATER BASED09.07.199138541.7532.010.5WATER BASED09.07.199138861.7535.012.0WATER BASED09.07.199139021.7532.010.1WATER BASED09.07.199139301.7534.09.1WATER BASED12.08.199139301.7534.09.6WATER BASED13.08.199139721.7540.08.6WATER BASED23.07.199139761.7540.012.0WATER BASED24.07.199139861.7539.010.5WATER BASED25.07.199139991.7534.012.4WATER BASED10.07.199140211.7545.010.5WATER BASED29.07.199140221.7543.012.0WATER BASED26.07.199140221.7543.012.0WATER BASED29.07.199140221.7530.011.0WATER BASED11.07.199140221.7528.09.6WATER BASED15.07.199140221.7543.010.5WATER BASED30.07.199140221.7530.010.1WATER BASED15.07.199140221.7527.09.6WATER BASED15.07.199140221.7531.09.6WATER BASED15.07.199140221.7528.07.7WATER BASED16.07.199140221.7531.09.1WATER BASED17.07.199140221.7527.07.2WATER BASED18.07.199140221.7524.05.7WATER BASED19.07.199140221.7525.06.2WATER BASED22.07.199140221.7535.06.7WATER BASED22.07.199140221.7540.09.6WATER BASED22.07.199140391.7543.010.5WATER BASED31.07.199140391.7540.09.6WATER BASED05.08.199140621.7544.09.6WATER BASED01.08.199140721.7544.011.0WATER BASED02.08.199141121.7541.010.1WATER BASED05.08.199141311.7540.010.5WATER BASED05.08.199141471.7538.08.6WATER BASED06.08.199141701.7538.09.6WATER BASED07.08.199141701.7542.09.1WATER BASED09.08.199141701.7541.08.6WATER BASED12.08.199141701.7541.08.6WATER BASED12.08.199141701.7544.08.6WATER BASED14.08.199141701.7537.07.7WATER BASED15.08.199141701.7535.06.7WATER BASED19.08.199141701.7535.06.7WATER BASED19.08.199141701.7548.010.1WATER BASED20.08.199141701.7545.09.6WATER BASED21.08.199141701.7538.010.5WATER BASED22.08.199141700.00WATER BASED26.08.199141701.7538.08.6WATER BASED08.08.199141701.7535.07.2WATER BASED16.08.199141701.7534.07.7WATER BASED19.08.199141701.75WATER BASED23.08.1991
Thin sections at the NPD
Thin sections at the NPDDepthUnit3718.50[m ]3724.80[m ]3734.50[m ]3745.45[m ]3752.65[m ]3755.29[m ]3771.76[m ]3774.72[m ]3782.79[m ]3794.70[m ]3798.40[m ]3818.51[m ]3824.77[m ]3828.25[m ]3844.10[m ]3849.20[m ]3854.55[m ]3869.97[m ]3902.00[m ]3879.55[m ]
Pressure plotsThe 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 plotsDocument nameDocument formatDocument size [MB]0.23