1/3-10
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General information
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Wellbore history
GeneralWell 1/3-10 is located on the Hidra High, ca 20 km south-south west of the Ula Field in the North Sea. It was drilled to appraise the oil and gas bearing Late Paleocene Forties Sandstone in the Oselvar structure, first discovered by the 1/3-6 well drilled by Elf Aquitaine Norway A/S in 1991. The main goal of the well was to acquire sufficient reservoir data to make a decision on future development of the Oselvar discovery.Operations and resultsAppraisal well 1/3-10 was spudded with the jack-up installation Mærsk Guardian on 25 October 2007 and drilled to TD at 3288 m in the Paleocene Lista Formation. The well was drilled and tested without significant technical problems. It was drilled with seawater / PHB down to 816 m, with KCl/Polymer mud from 816 to 1300 m, and with Carbo SEA OBM from 1300 to TD.The top of the Hordaland Group came in deep (19 m) compared to prognosis, as did the Balder and Sele Formations of the Rogaland Group (12 m and 5 m deep respectively). More significantly, a thicker than prognosed Sele Formation resulted in the target reservoir Forties sandstone coming in at 3153 m, 24 m deep compared to prognosis. The thickness of the Forties Sandstone however, was 52 m, which is only one meter thinner than prognosed. Of this thickness 32 m was designated as net reservoir using a porosity cut-off value of 10%. The average porosity was 17.7 % and the water saturation was 44.9%. The Forties Formation contained light oil with a free water level for the area estimated at 3245 m. Shows were only recorded in the target Forties Formation sandstones.The Forties Formation Sandstone was cored from 3159 to 3232 m with 99.8% recovery. An RCI log was run for pressure and fluid sampling. Four light oil gradients with increasing density downwards could be identified from these data. Light oil fluid samples were taken in Run 2A at two depths, 3162.2 m and 3186.3 m. Run 2D samples were taken at 3203.3 m (approximately 70% water and 30% oil), and at 3196.5 m (about 80% light oil and 20% water).The well was plugged back for sidetracking on 7 January 2008 as an oil and gas appraisal well.TestingThe Forties Formation was tested by an open hole ("barefoot") DST in the 8 1/2" section from 3158 to TD. The test produced 457 Sm3 oil and 212453 m3 gas /day through a 48/64" choke in the main flow period. The GOR was 465 m3/m3, the oil density was 0.791 g/cm3, and the gas gravity was 0.855 (air = 1), with 5 ppm H2S and 2.5 % CO2. -
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]250.003288.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom13159.03231.8[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]72.8Cores 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 availableDST0.000.00YES -
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 typeCONDUCTOR30215.036225.00.00LOTSURF.COND.18 5/8810.024816.00.00LOTINTERM.13 3/81294.017 1/21300.01.50LOTINTERM.9 5/83153.012 1/43153.01.90LOTOPEN HOLE3158.08 1/23288.00.00LOT -
Drill stem tests (DST)
Drill stem tests (DST) Test numberFrom depth MD
[m]To depth MD
[m]Choke size
[mm]1.03158328819.0Drill stem tests (DST) Test numberFinal shut-in pressure
[MPa]Final flow pressure
[MPa]Bottom hole pressure
[MPa]Downhole temperature
[°C]1.09.00038.000Drill stem tests (DST) Test numberOil
[Sm3/day]Gas
[Sm3/day]Oil density
[g/cm3]Gas grav. rel.airGOR
[m3/m3]1.04572124530.7910.855465 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]DSL RCI SV31623203MWD LWD - ...DGR DM BAT31533288MWD LWD - PCD117225MWD LWD - PCDC DGR EWR PWD8201300MWD LWD - PCDC DGR EWR PWD BAT13003158MWD LWD - PWD CTN ACAL ALD EWR..31533288VSP GR13653270WGI DSL RCI31603216 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit1171685305930593069315332053228 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured2111.0410.0SPUD MUD2251.0410.0SPUD MUD4261.0421.0SPUD MUD8051.0411.0SPUD MUD8161.2015.0SPUD MUD12520.00OIL (REGULAR)13001.7549.0OIL (REGULAR)13001.3017.0POLYMER17321.7547.0OIL (REGULAR)19641.7549.0OIL (REGULAR)22721.6046.0OIL (REGULAR)29201.7546.0OIL (REGULAR)29491.75513.0OIL (REGULAR)29541.7341.0OIL (REGULAR)31261.7349.0OIL (REGULAR)31581.7546.0OIL (REGULAR)31761.7347.0OIL (REGULAR)32321.3935.0OIL (REGULAR)32881.3937.0OIL (REGULAR)32881.3934.0OIL (REGULAR)33551.7146.0OIL (REGULAR)33821.6846.0OIL (REGULAR)35371.6649.0OIL (REGULAR)36321.6647.0OIL (REGULAR)