General information Attribute ValueWellbore name34/10-48 STypeEXPLORATIONPurposeWILDCATStatusP&APress releaseFactmaps in new windowMain areaNORTH SEAFieldDiscoveryWell name34/10-48Seismic locationlinje 2951 & CDP 3135Drilled in production licenceDrilling operatorStatoil ASA (old)Drill permit1071-LDrilling facilityDrilling days281Entered date17.03.2004Completed date22.12.2004Release date22.12.2006Publication date28.02.2008Purpose - plannedWILDCATReentryNOContentOILDiscovery wellboreYES1st level with HC, ageLATE JURASSIC1st level with HC, formationVIKING GP2nd level with HC, ageMIDDLE JURASSIC2nd level with HC, formationBRENT GPKelly bushing elevation [m]84.1Water depth [m]216.9Total depth (MD) [m RKB]7393.0Final vertical depth (TVD) [m RKB]2933.0Maximum inclination [°]92.6Bottom hole temperature [°C]107Oldest penetrated ageLATE TRIASSICOldest penetrated formationLUNDE FMGeodetic datumED50NS degrees61° 12' 53.78'' NEW degrees2° 16' 27.79'' ENS UTM [m]6787106.31EW UTM [m]461018.63UTM zone31NPDID wellbore4902
Wellbore historyGeneralWell 34/10-48 S was drilled on the Gullfaks Field in the Northern North Sea, from the Gullfaks C platform. The main objective was to test the hydrocarbon potential of the Brent Group in the Topas prospect. The secondary objectives were to test the hydrocarbon potential in 3 leads; the Nesle lead east of the Topas prospect, the U2 lead in the slope of the Gullfaks Horst and Late Jurassic at the base of the main bounding fault limiting the Gullfaks Structure to the east. The well should be completed as a producer.Operations and resultsWell 34/10-48 S was spudded from a preset 32" conductor at slot 29 on the Gullfaks C platform on 17 March 2004.The planned well was a very challenging one, with a complex and highly deviated well path. Deviation from vertical was 11 deg at 438 m and was increased to ca 66 deg from 1500 m. When entering the Lunde Formation inclination was 56 deg, and from ca 5500 m in the Brent Group and to TD the well path was kept approximately horizontal. It was planned drilled in 4 sections, 24", 17 1/2", 12 1/4" and 8 1/2". The planned TD of the well was 6848 m. Information gathered while drilling the 8 1/2" section led to a change in plans and the well path in the reservoir was changed and extended with 550 m. The well 48 S was drilled to 7393 m. The well was drilled with spud mud in the 24" section from 443 m to 1355 m, with Glydril mud in the 17 1/2" section from 1355 m to 2610 m, and with Versavert oil based mud in the remaining sections from 2610 m to TD.The well was classified as exploration well from 3600 m. The Lunde Formation was penetrated at 3657 m. Hydrocarbon filled sandstones in this Formation (the U2 lead) were encountered at 4272 m /2470 m TVD, while the sandstone layer at the base of the main bounding fault, at 4891 m / 2800 m TVD, was water filled. The Topas prospect was penetrated some 7.5 m shallow to prognosis. The well drilled through hydrocarbon filled Tarbert Formation and into water filled Ness Formation. Since the well drilled water filled Ness, Etive and Rannoch Formations the well path was revised and the Nesle lead was drilled higher on the structure. The well drilled through some hydrocarbon filled Late Jurassic sands (Intra Heather Formation sandstone) before entering hydrocarbon filled sands of the Ness and Tarbert Formations of the Topas prospect in the PL120 licence. The well path was steered down and the oil water contact was found at 7133 m /2929 m TVD RKB in the Tarbert Formation. The preliminary results of the well 34/10-48 S indicated that the well path had penetrated low on the Topas structure and that the well path was not ideal for production. It was therefore decided to drill a sidetrack and aim as high on the re-interpreted structure as possible.One core was cut in the Tarbert Formation from 5174 to 5207.15 m. MDT fluid samples were collected at 4372 m, 4455 m, 4492 m and 4533 m in the Lunde Formation. All samples contained oil with relatively high gas/oil ratio.Well bore 34/10-48 S was plugged back to 5060 m and permanently abandoned on 22 December 2004 as an oil discovery. Well side track 34/10-48 A was initiated.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]3600.007392.00
Cores at the NPD
Cores at the NPDCore sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom15174.05207.2[m ] Cores at the NPDTotal core sample length [m]33.2 Cores at the NPDCores available for sampling?YES
LithostratigraphyTop depth [m]Lithostrat. unit30111021122235723572528285136123657365746454645489150085008516151615311545655005843585659996143614364556455664073047304
LogsLog typeLog top depth [m]Log bottom depth [m]ARC6 ADN656085878ARC6 ADN658506221EMS GR MDT DN36705005EMS GR MDT UP50052600LWD - ARC ISONIC ADN826675106LWD - ARC6 ADN651067393LWD - ARC6 ADN6 TST651065850LWD - CDR224725LWD - CDR12872667MDT51407145MDT ECS CMR DN51406413MDT ECS CMR UP51496413
Casing and leak–off tests
Casing and leak–off testsCasing typeCasing diam.
[m]LOT/FIT mud eqv.
[g/cm3]Formation test typeSURF.COND.201283.0241287.00.00LOTINTERM.13 3/82661.017 1/22667.01.83LOTINTERM.9 5/85108.012 1/45109.00.00LOTOPEN HOLE7393.08 1/27393.00.00LOT
Drilling mudDepth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured6701.1218.0SEAWATER/CMC11531.1219.0SEAWATER/CMC12881.2027.0SEAWATER/CMC15201.2916.0GLYDRIL 1226671.5537.0GLYDRIL 1237591.6570.0VERSAVERT 4238251.6460.0VERSAVERT 4151051.6035.0VERSAVERT 4151091.5953.0VERSAVERT 4160571.6053.0VERSAVERT 4162441.5844.0VERSAVERT 4173931.5857.0VERSAVERT 41
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 [KB]0.22