General information Attribute ValueWellbore name25/1-11 ATypeEXPLORATIONPurposeAPPRAISALStatusP&APress releaseFactmaps in new windowMain areaNORTH SEAFieldDiscoveryWell name25/1-11Seismic locationNH9306R04 inline 1250 & xline 2593Drilled in production licenceDrilling operatorDet norske oljeselskap ASADrill permit1312-LDrilling facilityDrilling days16Entered date29.04.2010Completed date14.05.2010Plugged and abondon date14.05.2010Release date14.05.2012Publication date14.05.2012Purpose - plannedAPPRAISALReentryNOContentOIL/GASDiscovery wellboreNO1st level with HC, ageEOCENE1st level with HC, formationFRIGG FMKelly bushing elevation [m]40.0Water depth [m]107.0Total depth (MD) [m RKB]2410.0Final vertical depth (TVD) [m RKB]2265.0Maximum inclination [°]33Bottom hole temperature [°C]75Oldest penetrated ageLATE PALEOCENEOldest penetrated formationHEIMDAL FMGeodetic datumED50NS degrees59° 47' 25.12'' NEW degrees2° 13' 6.43'' ENS UTM [m]6628472.08EW UTM [m]456130.02UTM zone31NPDID wellbore6376
Wellbore historyGeneralWell 25/1-11 A is a sidetrack to the Storklakken well 25/1-11 R on the Frigg Ridge between the Frigg and Heimdal Fields in the North Sea. Well 25/1-11R found oil and gas in the Eocene Frigg Formation. The main objective of the sidetrack was to prove the vertical extension of the hydrocarbon column in the Frigg reservoir and to find a potential gas-oil contact. An additional objective was to achieve better control of the Frigg/Odin sand pinch out line.Operations and resultsWell 25/1-11 A was sidetracked on 26 April 2010 from a window in the 13 3/8" casing at 1099 m in the primary well bore. The well was drilled with the semi-submersible installation Aker Barents to TD at 2410 m (2264.5 m TVD) in the Palecocene Heimdal Formation. The well was drilled with Versatec oil based mud from kick-off to TD.The Frigg Formation came in at 2234 m (2110 m TVD). The upper section down to 2274 m (2145.5 m TVD) was dominantly claystone with thin sandstone stringers. In these sandstone stringers a gas gradient was found. In the main Frigg Sandstone an oil gradient was seen with an oil-down-to contact at 2286 m (2156 m TVD). No water zone was encountered. The gas gradient indicates the possibility of a GOC at 2146.1 m TVD. The pressure regimes in the Frigg Formation in the two well bores are slightly different, indicating a pressure barrier in the Frigg reservoir section between the two wellbores. In the lower section of the well a separate water gradient was found in the Heimdal Formation sandstone with a slightly higher pressure regime compared to the Frigg Sandstone.No cores were cut. The MDT was run for pressure points and fluid samples. In this operation the MDT got stuck, but was freed and retrieved to surface after a 50 hours cut and thread operation. Eighteen good pressure points out of 24 tests were obtained, and a water sample was taken at 2320 m.The well was permanently abandoned on 14 May 2010 as an oil and gas appraisal.TestingNo drill stem test was performed.
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]1110.002410.00
Palynological slides at the NPD
Palynological slides at the NPDSample depthDepth unitSample typeLaboratory2261.0[m]DCPETROSTR2270.0[m]DCPETROS2273.0[m]DCPETROS2288.0[m]DCPETROS2297.0[m]DCPETROS2306.0[m]DCPETROS2315.0[m]DCPETROS2324.0[m]DCPETROS2333.0[m]DCPETROS2342.0[m]DCPETROS2351.0[m]DCPETROS2360.0[m]DCPETROS2369.0[m]DCPETROS2378.0[m]DCPETROS2387.0[m]DCPETROS2396.0[m]DCPETROS2405.0[m]DCPETROS2410.0[m]DCPETROS
LogsLog typeLog top depth [m]Log bottom depth [m]MDT23200MSCT22322395MWD LWD - GR RES10992407PEX AIT10622413
Casing and leak–off tests
Casing and leak–off testsCasing typeCasing diam.
[m]LOT/FIT mud eqv.
[g/cm3]Formation test typeINTERM.13 3/81091.017 1/21178.00.00LOTOPEN HOLE2410.012 1/42410.00.00LOT
Drilling mudDepth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured11431.2422.0Glydril13281.3934.0Versatec17361.3936.0Versatec OBM19781.2120.0Glydril24501.3933.0Versatec OBM