30/3-7 B
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General information
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Wellbore history
GeneralWell 30/3-7 S was planned to drill the B-Prospect of the Veslefrikk field, but found hydrocarbons in various small fault segments on the edge of the Veslefrikk horst, and never reached the B-Prospect. Well 30/3-7 A, that was plugged back, was the first well to penetrate the Brent Group in the B-Prospect as a pilot hole for 30/3-7 B. Well 30/3-7 B was the first well to be drilled through the C-segment, and into the B-prospect west of the Main Veslefrikk Field.The main objectives for well 30/3-7 B were to explore the sand potential and possible hydrocarbons in the C-segment, and in the B-prospect. The well would be utilized as a producer if sufficient amount of hydrocarbons were found. Because of total depth deeper than 4000 m TVD the well was classified as a HPHT well.Operations and resultsWildcat well 30/3-7 B was drilled from the fixed surface installation Veslefrikk A as a sidetrack from well 30/3-7 S higher up than 30/3-7A (2066 m TVD/2780 m MD versus 2397 m TVD/ 3336 m MD). It was kicked off on 20 May 1998. The well was drilled to 5970 m MD/4217 m TVD RKB in the Dunlin Group. The mud used, from kick-off to TD, was Interdrill, a pseudo-oil based mud system.The base Cretaceous/top Viking Group was penetrated at 4259 m MD/3100 m TVD, 10 m shallow. Hydrocarbon filled Brent Group slump blocks (approximately 40 m reservoir sandstone) was encountered just below base Cretaceous at 4271.5 m MD/3107.7 m TVD. The lower 20 m is recognized as the Oseberg informal Formation B2A/B.Two cores were cut (7 and 4 m) just above the main slump plane. They consisted of brittle Drake Formation shales that caused frequent jamming and very short cores. The slump plane was penetrated only 5 m shallower than prognosed.The C-segment contains hydrocarbon filled Intra Dunlin Sand (IDS), which came in 32 m shallow. The reservoir quality in this location is poor. Three major faults have been observed between the C-segment and the B-prospect. The throws are approximately 400, 150 and 400 meters.The fault block VF west 1 (produced in well 30/3-7S) was encountered close to prognosis, but the stratigraphy came in deeper, with unexpected 24 m TVD of sandy Ness Fm. The main fault to the B-prospect came in 80 m further to the west than prognosed, giving a total width of the VF west 1 block of 200 m. Two cores were cut from 4346 m to 4358.5 m in the L-prospect, just above the main slump plane. One oriented core was cut from 5715 m to 5740 m in the Oseberg Informal Formation in the B-prospect. Two MDT runs were made in the interval 4290 m to 5917 m, for pressure points and fluid sampling. Fluid samples were taken at 4290.5 m (mud filtrate and gas), 4674.9 m, and 5902.8 m.The well was completed on 4 August 1998 as an oil/gas discovery. In January 1999 it was perforated over the intervals 5139 -5145 and 5163 - 5179 m MD and reclassified to production test well 30/3-T-7 B.TestingNo drill stem test was performed. -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom14346.04353.2[m ]24354.04358.5[m ]35715.05740.2[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]37.0Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
Core photos
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Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit231783963267026702804284431163116343736934261426142724272430443504350437844394611494849485124512452025229525953265352535255145514559356745693577757775897 -
Composite logs
Composite logs Document nameDocument formatDocument size [MB]pdf0.49 -
Geochemical information
Geochemical information Document nameDocument formatDocument size [MB]pdf0.57 -
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].pdf2.14.pdf22.98 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]AMS CNT LDL BHC CMR GR42085960MDT CMR GR51315355MDT GR42904396MDTCMR GR43015903MWD - GR RES DIR27845970UIB AIT00 -
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 typeINTERM.9 5/84287.012 1/44290.01.65LOTLINER55962.08 3/85962.00.00LOT -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured27801.6046.0INTERDRILL NT42921.5341.0INTERDRILL NT47781.5346.0INTERDRILL NT51251.5345.0INTERDRILL NT51701.5340.0INTERDRILL NT52721.5041.0INTERDRILL NT53201.5342.0INTERDRILL NT53771.5343.0INTERDRILL NT57571.5348.0INTERDRILL NT59701.5348.0INTERDRILL NT -
Thin sections at the Norwegian Offshore Directorate
Thin sections at the Norwegian Offshore Directorate DepthUnit4346.40[m ]4351.65[m ] -
Pressure plots
Pressure plots The 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 plots Document nameDocument formatDocument size [MB]pdf0.23