7/12-3 A
Export: PDF
-
General information
-
Wellbore history
GeneralWell 7/12-3 A is a geological sidetrack to 7/12-3 on the western flank of the 7/12-2 Ula discovery in the North Sea. The primary objective was to establish the oil-water level in the Ula structure.The well is type well for the Mandal Formation.Operations and resultsOn 4 June 1977 appraisal well 7/12-3 A was kicked off from below the 13 3/8” casing shoe in well 7/12-3 at a depth of 1720. The semi-submersible installation Norskald drilled the well to TD at 4191 m (4011 m TVD) in the Permian Zechstein Group.Well 7/12-3A penetrated the reservoir at 3638.5 (3506.8 m TVD). The cores showed oil staining, cut and fluorescence. Wire line logs and testing showed this to be immovable oil, and indicated an oil water transition zone to a depth of 3693.5. (3555.3 m TVD). One hundred and eighty-nine meters of Ula Formation reservoir were encountered representing a true thickness of 168.9 m, and a net to gross ratio of 0.83 assuming a 10% porosity cut off on the computer-processed log.Seven full hole cores were cut from 3642.0 to 3730.0 m. RFT fluid samples were taken at 3675.5 m (salt water and mud filtrate) and 3688.5 m (salt water with traces of gas and oil/oil-water emulsion).The well was permanently abandoned on 6 September 1977 as a dry well with shows.TestingDST 1 tested the interval 3771.0 to 3715.5m. The test flowed 192 m3 saline formation water /day through a 32/64 choke. The DST temperature was 146.7 °C.DST 2 teste the interval 3680.0 to 3669.5 m. The test flowed 509 m3 saline formation water with trace oil /day through a 32/64 choke. The DST temperature was 145.6 °C. -
Cuttings at the Norwegian Offshore Directorate
Cuttings at the Norwegian Offshore Directorate Cuttings available for sampling?NOCuttings at the Norwegian Offshore Directorate Cutting sample, top depth [m]Cutting samples, bottom depth [m]1730.004114.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom13642.53660.0[m ]23660.03678.3[m ]33678.33692.2[m ]43692.23697.6[m ]53697.63698.0[m ]63700.03718.0[m ]73718.03730.0[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]85.5Cores 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 typeCONDUCTOR30169.036174.00.00SURF.COND.20466.026470.00.00INTERM.13 3/81679.017 1/21686.00.00INTERM.9 5/83601.012 1/23612.00.00OPEN HOLE4190.08 1/24190.00.00 -
Drill stem tests (DST)
Drill stem tests (DST) Test numberFrom depth MD
[m]To depth MD
[m]Choke size
[mm]1.0377137160.02.0367336620.0Drill stem tests (DST) Test numberFinal shut-in pressure
[MPa]Final flow pressure
[MPa]Bottom hole pressure
[MPa]Downhole temperature
[°C]1.02.0Drill stem tests (DST) Test numberOil
[Sm3/day]Gas
[Sm3/day]Oil density
[g/cm3]Gas grav. rel.airGOR
[m3/m3]1.02.0 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CBL16002500CBL16002500CBL VDL GR CCL33954105CST32603585CST36054125DLL RXO GR SP CAL35993827FDC CNL GR37734130FDC CNL GR CAL35993827ISF BHC GR SP16813586ISF BHC GR SP35994016ISF BHC GR SP35993825ISF BHC GR SP37664188RFT36264080RFT36503897RFT36750RFT36880TEMP16501979WST17204188 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit9615652655265526922731276228262826294731953261326135143514356036383638382739294095 -
Geochemical information
Geochemical information Document nameDocument formatDocument size [MB]pdf0.27 -
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]pdf2.32pdf7.06pdf13.26 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured17201.45waterbased20481.46waterbased28381.45waterbased33461.45waterbased36121.46waterbased -
Palynological slides at the Norwegian Offshore Directorate
Palynological slides at the Norwegian Offshore Directorate Sample depthDepth unitSample typeLaboratory3451.0[m]DCOD3460.0[m]DCOD3469.0[m]DCOD3481.0[m]DCOD3490.0[m]DCOD3499.0[m]DCOD3505.0[m]DCOD3511.0[m]DCOD3514.0[m]DCOD3520.0[m]DCOD3526.0[m]DCOD3529.0[m]DCOD3535.0[m]DCOD3541.0[m]DCOD3544.0[m]DCOD3550.0[m]DCOD3556.0[m]DCOD3559.0[m]DCOD3571.0[m]DCOD3580.0[m]DCOD3589.0[m]DCOD3601.0[m]DCOD