General information Attribute ValueWellbore name34/4-1TypeEXPLORATIONPurposeWILDCATStatusP&AFactmaps in new windowMain areaNORTH SEAFieldDiscoveryWell name34/4-1Seismic locationDrilled in production licenceDrilling operatorSaga Petroleum ASADrill permit217-LDrilling facilityDrilling days159Entered date11.07.1979Completed date16.12.1979Release date16.12.1981Publication date26.05.2009Purpose - plannedWILDCATReentryNOContentOILDiscovery wellboreYES1st level with HC, ageLATE TRIASSIC1st level with HC, formationLUNDE FMKelly bushing elevation [m]25.0Water depth [m]377.0Total depth (MD) [m RKB]2916.0Final vertical depth (TVD) [m RKB]2912.0Maximum inclination [°]8.8Bottom hole temperature [°C]103Oldest penetrated ageMIDDLE TRIASSICOldest penetrated formationTEIST FM (INFORMAL)Geodetic datumED50NS degrees61° 32' 49.23'' NEW degrees2° 16' 23.66'' ENS UTM [m]6824096.50EW UTM [m]461368.88UTM zone31NPDID wellbore422
Wellbore historyGeneralWildcat well 34/4-1 was drilled on the rotated fault block systems on the Tampen Spur area of the Northern North Sea. The objective of the well was to test the stratigraphic sequence below the Base Cretaceous Unconformity. The primary target was the Intra Triassic "Carnian Sandstone", which was known from two wells in block 33/12 where it constitutes more than 100 m silty, argillaceous, partly calcareous cemented sandstone. The secondary targets were possible reworked Late Jurassic sandstones immediately below the Unconformity, and by possible sands associated with stratigraphically undefined seismic reflectors between Base Cretaceous and Carnian level.Operations and resultsWell 34/4-1 was spudded with the semi-submersible installation Byford Dolphin on 11 July 1979. The well was first drilled to 2961 m. When pulling out of hole to change bit it got stuck. The bit could not be worked free and the drill string was eventually backed off and left in the hole. A sidetrack was made from 2484 m and drilled to final TD at 2916 m in the Triassic Teist Formation. The well was drilled with seawater and viscosity slugs down to 844 m, with Drispac/Unical/gypsum mud from 844 m to 1988 m, and with Drispac/Unical mud from 1988 m to TD, including sidetrack.The well penetrated Tertiary, Cretaceous and Triassic rocks with a hiatus ranging from Late Triassic to Early CretaceousSecondary target for the well was reworked Late Jurassic sediments immediately below Base Cretaceous. Such deposits were not established. The Triassic sandstones (Lunde Formation) were encountered at 2508 m and contained oil over a column of more than 100 m. No definite OWC was seen, but it could be estimated to be at 2618 m. Numerous shows on sandstone stringers were observed in the Cretaceous from ca 2025 m (top Kyrre Formation) and down to top of the Triassic reservoir. No shows were observed below 2622 m.Eleven cores were cut in the Lunde Formation. Cores 1 and 2 were cut in the primary well bore, and the first of these was a mis-run. The remaining nine cores were cut in the side track. Two RFT segregated fluid samples were taken. The first, at 2541 m, recovered oil, gas and mud filtrate. The second, at 2639.5 m, recovered formation water and mud filtrate.The well was permanently abandoned on 16 December 1979 as an oil discovery.TestingTwo drill stem tests were performed in the Lunde Formation.DST 1 tested the interval 2608 - 2613 m. It produced a total of 1.65 m3 salt water at a rate of approximately 11 m3 /day (79 bbls/day). The BHT in the test was 94.4 deg CDST 2 tested the interval 2510 - 2536 m. The average rate in the final flow in this test was 238 m3/day of oil through a 1/4" choke. Average GOR was 120 m3/m3, oil Gravity was 0.82 g/cm3 (41.7 deg API) and the gas gravity was 0.712 (air = 1). The BHT in the test was 90.6 deg C.
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]530.002910.00
Cores at the NPD
Cores at the NPDCore sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom10.022509.22510.5[m ]32516.02531.8[m ]42531.82539.9[m ]52541.42544.1[m ]62557.02563.5[m ]72570.82589.8[m ]82589.82608.9[m ]92608.82614.7[m ]102615.32617.3[m ]112665.02674.6[m ] Cores at the NPDTotal core sample length [m]89.9 Cores at the NPDCores available for sampling?YES
Documents – reported by the production licence (period for duty of secrecy expired)
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]CBL4031975CBL19502499CST24802521CST26772915DLL24992911FDC CNL GR23902915HDT19762899ISF SONIC GR5212515ISF SONIC MSFL SP GR CAL24992914MSFL24002518NGT24992915RFT25122516RFT25412640VELOCITY5242914
Casing and leak–off tests
Casing and leak–off testsCasing typeCasing diam.
[m]LOT/FIT mud eqv.
[g/cm3]Formation test typeCONDUCTOR30521.036521.00.00LOTSURF.COND.20830.026845.01.68LOTINTERM.13 3/81975.017 1/21991.01.94LOTINTERM.9 5/82499.012 1/42515.01.84LOTLINER72703.08 1/22916.00.00LOT
Drilling mudDepth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured8601.1542.0waterbased12751.2740.0waterbased18101.4849.0waterbased20801.7746.0waterbased23701.7850.0waterbased25651.7752.0waterbased29001.7759.0waterbased
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]0.21