7219/8-1 S
Export: PDF
-
General information
-
Wellbore history
GeneralExploration well 7219/8-1 S is located in the Bjørnøya Sør area west of the Veslemøy High. This was a new geological province and hence the well was a true wildcat. The well was drilled up-dip of a rotated fault block at Late to Middle Jurassic level. The primary purpose of the well 7219/8-1 S was to test the Middle Jurassic Stø Formation. A secondary objective was to test possible sandstone in Late Jurassic Hekkingen Formation, and finally, to test possible sandstone in a defined stratigraphic trap in the Early Cretaceous sequences.Operations and resultsWell 7219/8-1 S was spudded with the semi submersible installation Ross Rig on 5 October 1992 and drilled to TD at 4611.5 m, 91 m into the Early - Middle Jurassic Stø Formation. The well was drilled deviated towards northwest with a direction of approximately 294 degrees with approximately 22 degrees inclination. Kick off point was at 1396 m. No shallow gas was identified. The well was drilled with spud mud down to 1018 m and with KCl / polymer / Anco 208 (glycol additive) mud from 1018 m to TD. It was one of the first to be drilled with a glycol mud system to inhibit reactve shales.Down to the Base Cretaceous at 3471.5 m (3343 m TVD RKB), the well penetrated mainly claystones. The shallowest prospect, the Cretaceous sequence, was penetrated in a distal position, and hence was most likely shaled out. The Jurassic comprised the Late Jurassic Hekkingen and Fuglen Formations and the Early to Middle Jurassic Stø Formation. The secondary Hekkingen prospect was penetrated about 720 m deeper than prognosed and was only 9 m thick. Pressure test indicated a tight formation. The large difference between the prognosed and actual depth was mainly due to a much thicker Early Cretaceous sequence than prognosed. The main prospect, the Stø Formation, was penetrated 450 m deeper than prognosed. The Sandstone with porosity in order of 5-8%, was water bearing. The relatively tight sandstone of the Stø Formation is explained by the large maximum depth of burial in addition to present depth of burial (an uplift/erosion of 800 m to 1000 m can be estimated).Traces of hydrocarbon shows were seen in some silty parts in the Cretaceous from 2400 m to 2430 m (2349 - 2370 m TVD RKB) in the Knurr Formation and from 2595 m to 2652 m (2532 - 2585 m TVD RKB) in the Knurr Formation. Otherwise weak shows were recorded on sidewall cores from claystones in the Early Cretaceous to Late Jurassic interval 2815 m to 3740 m. Organic geochemical screening analyses show consistently high TOC over this interval (typically 2 % to 3.8 %). The maturity is quite advanced (%Ro typically 0.9 to 1.5) and increases with depth as the hydrogen index decreases from about 120 to about 50 mg/g HC. The glycol used in the mud does not appear to have affected these data. It thus seems that the source potential of the shales in this sequence is much reduced by thermal maturation in the well.One core was cut in the Hekkingen Formation over the interval: 4270 m to 4278 m (4085 - 4092 m TVD RKB). This core comprised only claystones. Two cores were cut in the sandstones of the Stø Formation over the following intervals: 4550 m to 4551 m (4347 - 4348 m TVD RKB) and 4597 m to 4611.5 m (4391 - 4404 m TVD RKB). These cores comprised very tight sandstones with no shows. Formation Multi Tester (FMT) pressure tests were attempted both in the sandstones of the Hekkingen and the Stø Formation. Only those from the Stø Formation gave pressure data, but from these no reliable pressure gradient could be extracted. A segregated sample at 4531.7 (4329.5 m TVD RKB) in the Stø Formation gave formation water with no traces of hydrocarbons.The well was plugged and abandoned as a dry hole on 26 December 1992.TestingNo drill stem test was performed -
Cuttings at the Norwegian Offshore Directorate
Cuttings at the Norwegian Offshore Directorate Cuttings available for sampling?YESCuttings at the Norwegian Offshore Directorate Cutting sample, top depth [m]Cutting samples, bottom depth [m]1020.004596.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom14270.04277.4[m ]24550.04551.0[m ]34597.04611.5[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]22.9Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
Core photos
-
Casing and leak–off tests
Casing and leak–off tests Casing typeCasing diam.
[inch]Casing depth
[m]Hole diam.
[inch]Hole depth
[m]LOT/FIT mud eqv.
[g/cm3]Formation test typeCONDUCTOR30478.036483.00.00LOTINTERM.20927.026947.01.31LOTINTERM.13 3/82128.017 1/22149.01.49LOTINTERM.9 5/83367.012 1/43378.01.98LOTOPEN HOLE4611.08 1/24611.00.00LOT -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CORE5071000CORE10151557CORE15252120CORE21552630CORE26273350COREGUN33704070COREGUN41004569DIFL ACL GR33634455DIFL ACL GR44004607DIFL ACL ZDL CN GR21243372DIFL ACL ZDL GR4761017DIFL ACL ZDL GR9262133DIPLOG GR21243353DIPLOG GR33704455DLL MLL GR44834543FMT40704261FMT43294601FMT45314588MWD - CDR GR DIR4761017MWD - SN RES GR DIR9262133MWD - SN RES GR DIR21243372MWD - SN RES GR DIR33634455VSP12103360VSP33304450ZDL CN GR33634437ZDL CN GR44004605 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit39355455415451545208024943472432845214521 -
Composite logs
Composite logs Document nameDocument formatDocument size [MB]pdf0.68 -
Geochemical information
Geochemical information Document nameDocument formatDocument size [MB]pdf3.51 -
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]pdf18.64 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured5161.03WATER BASED5161.04WATER BASED6001.20WATER BASED8631.30WATER BASED10181.30WATER BASED14801.1719.0WATER BASED16831.1720.0WATER BASED18081.1620.0WATER BASED19171.1622.0WATER BASED20861.1720.0WATER BASED21261.3024.0WATER BASED21491.2122.0WATER BASED23181.3025.0WATER BASED24801.3025.0WATER BASED25261.3025.0WATER BASED25881.3026.0WATER BASED26961.3026.0WATER BASED27641.3026.0WATER BASED28401.3026.0WATER BASED28951.3021.0WATER BASED30721.3024.0WATER BASED31611.3525.0WATER BASED32221.3525.0WATER BASED32491.3525.0WATER BASED33451.3726.0WATER BASED33781.4328.0WATER BASED34231.4827.0WATER BASED35591.5028.0WATER BASED37451.5628.0WATER BASED38821.5627.0WATER BASED38831.4330.0WATER BASED39501.5629.0WATER BASED40051.5629.0WATER BASED41801.5630.0WATER BASED42351.5629.0WATER BASED42781.6227.0WATER BASED43711.6430.0WATER BASED44551.6730.0WATER BASED44601.6728.0WATER BASED45331.6726.0WATER BASED45491.6727.0WATER BASED45501.6726.0WATER BASED45511.6725.0WATER BASED45531.6724.0WATER BASED45791.7027.0WATER BASED46001.7023.0WATER BASED46121.7025.0WATER BASED -
Thin sections at the Norwegian Offshore Directorate
Thin sections at the Norwegian Offshore Directorate DepthUnit4610.00[m ]4604.50[m ]4601.80[m ]