25/11-5
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General information
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Wellbore history
GeneralWell 25/11-5 was drilled ca 4 km north west of the 25/11-1 Balder discovery well on the Utsira High in the North Sea. The well was designed to evaluate a sand build up and/or structural closure at the Middle Paleocene horizon top. The location was mapped structurally high to the adjacent wells 25/11-1, 25/11-2, 25/10-1, and 25/10-3.Operations and resultsAppraisal well 25/11-5 was spudded with the drillship Drillmaster on 3 April 1974 and drilled to TD at 2164 m in Triassic red-grey clays, and grey-green shale. Sloughing shale was the only drilling problem and this was overcome by converting the Drispac mud system to a ligno-gel seawater mud system. The well was drilled with Drispac from approximately 1000 to 1400 m, and with lignosulphonate/gel/seawater from ca 1400 m to TD.The well penetrated the Utsira Formation and a Skade Formation sand and then entered a ca 700 m thick section of shales belonging to the lower Hordaland Group before top Balder formation was encountered at 1661 m. Significant oil bearing sands in the interval from 1714 to 1771 m were confirmed by sidewall cores and Schlumberger electric logs. The lower part of this interval tested oil at good rates. Additional shows in traces of sand in cuttings at 1838 - 1847 m were believed to be sloughings from the oil sand above.One conventional core was cut from 1723.3 to 1725.5 m. Six attempts at FIT's were attempted with one successful at 1744.1 m. This test recovered 0.33 Sm3 gas, 4.5 l oil, 2.3 l filtrate and 0.8 l mud.The well was permanently abandoned on 8 May1974 as an oil appraisal.TestingA test through perforations at 1750 to 1765 m in the Hermod Formation produced at an average rate of 634 Sm3 oil and 29283 Sm3 gas /day. The GOR was 46.1 Sm3/Sm3 and the oil gravity was 24.2 deg API (0.91 g/cm3). -
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]198.122164.08 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom15654.05661.0[ft ]Cores at the Norwegian Offshore Directorate Total core sample length [m]2.1Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
Oil samples at the Norwegian Offshore Directorate
Oil samples at the Norwegian Offshore Directorate Test typeBottle numberTop depth
MD [m]Bottom depth
MD [m]Fluid typeTest timeSamples availableDSTDST11750.001765.0030.04.1974 - 00:00YES -
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 typeCONDUCTOR30187.036190.00.00LOTSURF.COND.13 3/8397.017 1/2411.00.00LOTINTERM.9 5/81397.012 1/41412.00.00LOTLINER71890.08 1/22164.00.00LOT -
Drill stem tests (DST)
Drill stem tests (DST) Test numberFrom depth MD
[m]To depth MD
[m]Choke size
[mm]1.0175017650.0Drill stem tests (DST) Test numberFinal shut-in pressure
[MPa]Final flow pressure
[MPa]Bottom hole pressure
[MPa]Downhole temperature
[°C]1.017.800Drill stem tests (DST) Test numberOil
[Sm3/day]Gas
[Sm3/day]Oil density
[g/cm3]Gas grav. rel.airGOR
[m3/m3]1.0636283710.91044 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]DIL3962162DIPMETER13972162FDC CNL13972163SGR3962161VELOCITY4572154 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit1475817007597599611661166116981701172417311771177317981873191719351950195019552087 -
Geochemical information
Geochemical information Document nameDocument formatDocument size [MB]pdf0.82 -
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]pdf1.35pdf4.69 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured1880.00seawater/ge14001.23seawater/lg21631.22water/spers -
Palynological slides at the Norwegian Offshore Directorate
Palynological slides at the Norwegian Offshore Directorate Sample depthDepth unitSample typeLaboratory1726.4[m]CRRI1727.4[m]CRRI1728.4[m]CRRI1729.1[m]CRRI1730.4[m]CRRI1730.9[m]CRRI1731.4[m]CRRI1731.7[m]CRRI1732.0[m]CRRI1732.7[m]CRRI1732.8[m]CRRI2450.0[ft]DC2480.0[ft]DC2540.0[ft]DC2630.0[ft]DC2720.0[ft]DC2810.0[ft]DC2900.0[ft]DC2990.0[ft]DC3080.0[ft]DC3170.0[ft]DC3260.0[ft]DC3350.0[ft]DC3440.0[ft]DC3530.0[ft]DC3620.0[ft]DC3710.0[ft]DC3800.0[ft]DC3890.0[ft]DC3920.0[ft]DC3980.0[ft]DC4070.0[ft]DC4110.0[ft]DC4170.0[ft]DC4270.0[ft]DC4290.0[ft]DC4330.0[ft]DC4370.0[ft]DC4470.0[ft]DC4490.0[ft]DC4530.0[ft]DC4570.0[ft]DC4650.0[ft]DC4740.0[ft]DC4830.0[ft]DC4920.0[ft]DC5010.0[ft]DC5100.0[ft]DC5190.0[ft]DC5220.0[ft]DC5250.0[ft]DC5280.0[ft]DC5280.0[ft]DC5310.0[ft]DC5340.0[ft]DC5370.0[ft]DC5400.0[ft]SWC5400.0[ft]DC5430.0[ft]DC5460.0[ft]DC5470.0[ft]SWC5508.0[ft]SWC5546.0[ft]SWC5560.0[ft]DC5570.0[ft]DC5580.0[ft]DC5600.0[ft]DC5616.0[ft]SWC5620.0[ft]DC5633.0[ft]DC5654.0[ft]C5666.0[ft]SWC5670.0[ft]DC5687.0[ft]SWC5698.0[ft]SWC5700.0[ft]DC5710.0[ft]SWC5730.0[ft]DC5760.0[ft]DC5790.0[ft]DC5820.0[ft]DC5826.0[ft]SWC5850.0[ft]DC5866.0[ft]SWC5880.0[ft]DC5910.0[ft]DC5940.0[ft]DC5970.0[ft]DC6000.0[ft]DC6030.0[ft]DC6060.0[ft]DC6120.0[ft]DC6164.0[ft]SWC6210.0[ft]DC6274.0[ft]SWC6300.0[ft]DC6400.0[ft]DC6410.0[ft]DC6440.0[ft]DC6480.0[ft]DC6490.0[ft]DC6580.0[ft]DC6680.0[ft]DC6737.0[ft]SWC6790.0[ft]DC6840.0[ft]DCRRI6880.0[ft]DC6980.0[ft]DC7080.0[ft]DC