1/2-1
Export:
PDF
![PDF icon](https://factpages.sodir.no/Images/file-pdf.png)
-
General information
-
Wellbore history
GeneralWell 1/2-1 is located in the Central Graben, about 200 m from the UK border in the North Sea. The main objective was Paleocene sands of the Rogaland Group. The secondary target was the chalk formations, although these were possibly not enough fractured to represent a reservoir.Operations and resultsWildcat well 1/2-1 was spudded with the semi-submersible installation Ross Isle on 20 March 1989 and drilled to TD at 3574 m in the Late Cretaceous Tor Formation. While cutting of core no 7, the elevators accidentally opened and dropped the string. Two attempts were made to recover the string with no success. The hole was sidetracked from 3078.5 m and core no 8 was cut. The well was drilled with seawater down to 645 m, with native mud (water mixed with clays from the borehole itself) from 645 m to1525 m, and with seawater from 1525 m to TD. No shallow gas was detected in the hole.The Forties Formation came in at 3121 m. The formation was hydrocarbon bearing down to 3142.5 m as confirmed by both electric logs and the RFT pressure gradient. The reservoir sandstones of the Forties Formation showed good to excellent reservoir properties. Average core porosity was 18.5% and test permeability was measured to 49 mD.Shows on cores were recorded down to core # 8 where they gradually decreased to zero at 3166 m. From the RFT data two water gradients were identified below the oil zone. A shift of 8 psi between them suggested the existence of an impermeable barrier around 3160.2 and 3162 m. Core saturations and fluorescence indicated the potential existence of a thin (4 m) oil zone below this barrier. This zone was not identified from the logs and was not evaluated for a test due to lack of data at that point.The Ekofisk formation was encountered at 3407 m, and the Tor formation at 3514 m. Both formations were water bearing.A total of 8 cores were cut in the Forties Formation, seven in the first hole and the eighth in the sidetrack. No wire line fluid samples were taken.The well was permanently abandoned on 4 June 1989 as an oil/gas discovery.TestingTwo intervals were perforated and tested with the intention to first test the oil zone and then open up a deeper zone to produce and sample formation water. The perforated intervals were 3122 - 3137 m in the oil zone and 3145.5 - 3157.7 m in the water zone. The oil test produced up to 859 Sm3 oil and 57200 Sm3 gas/day on a 64/64" choke. The GOR was 67 Sm3/Sm3 and the oil gravity was 42.5 deg API. The maximum temperature recorded during the test was 133.8 deg C. Analysis of the final co-mingled oil + water test confirmed that the lower perforation interval produced only water. This confirmed the contact at 3142.5 m to be an OWC. -
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]658.363573.78 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom110208.010208.4[ft ]210216.010233.0[ft ]410256.010286.0[ft ]510286.010358.0[ft ]610358.010364.6[ft ]710368.010377.6[ft ]810368.010395.3[ft ]Cores at the Norwegian Offshore Directorate Total core sample length [m]49.7Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
Core photos
-
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 availableDSTDST13122.303137.0027.05.1989 - 06:00YES -
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 typeCONDUCTOR30170.036171.00.00LOTINTERM.20645.026648.01.69LOTINTERM.13 3/81524.017 1/21531.01.82LOTINTERM.9 5/83052.012 1/43056.01.88LOTLINER73569.08 1/23576.00.00LOT -
Drill stem tests (DST)
Drill stem tests (DST) Test numberFrom depth MD
[m]To depth MD
[m]Choke size
[mm]1.03122313725.4Drill stem tests (DST) Test numberFinal shut-in pressure
[MPa]Final flow pressure
[MPa]Bottom hole pressure
[MPa]Downhole temperature
[°C]1.0Drill stem tests (DST) Test numberOil
[Sm3/day]Gas
[Sm3/day]Oil density
[g/cm3]Gas grav. rel.airGOR
[m3/m3]1.0859570000.81066 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CST GR6663557DIL SLS GR6453052DLL MSFL GR30523572FMS GR30523576LDL CNL NGT6453575MWD - GR RES DIR3085023RFT GR30593208SLS GR30523573TEST12TEST23TEST400VSP6313468 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit94177730593059312132753335340734073514 -
Geochemical information
-
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]pdf1.76pdf155.63 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured1711.04WATER BASED29.03.19892791.04WATER BASED29.03.19895461.04WATER BASED29.03.19895641.04WATER BASED29.03.19896481.04WATER BASED29.03.19896501.04WATER BASED29.03.19896511.0514.05.7WATER BASED30.03.198911971.1662.01.9WATER BASED31.03.198915311.4421.03.4WATER BASED04.04.198915311.448.016.3WATER BASED03.04.198915311.449.014.4WATER BASED03.04.198915311.4435.03.8WATER BASED03.04.198917831.4420.03.8WATER BASED05.04.198921991.5023.010.5WATER BASED06.04.198925041.5320.09.6WATER BASED07.04.198929061.5819.011.0WATER BASED10.04.198930501.6211.07.7WATER BASED10.04.198930561.6215.07.7WATER BASED11.04.198930561.6215.07.7WATER BASED11.04.198930561.6411.05.7WATER BASED12.04.198930561.6413.05.7WATER BASED14.04.198930561.6413.04.8WATER BASED17.04.198930561.6413.04.8WATER BASED17.04.198930561.6413.04.8WATER BASED17.04.198930561.6214.07.2WATER BASED10.04.198930561.6412.05.7WATER BASED13.04.198930591.6118.06.2WATER BASED27.04.198930711.6115.04.8WATER BASED26.04.198931091.6416.08.1WATER BASED17.04.198931091.6416.08.1WATER BASED17.04.198931091.6414.07.7WATER BASED17.04.198931091.6414.07.7WATER BASED17.04.198931091.6416.08.1WATER BASED17.04.198931091.6414.07.7WATER BASED17.04.198931141.6416.07.2WATER BASED19.04.198931171.6118.06.7WATER BASED28.04.198931251.6419.08.1WATER BASED19.04.198931261.6319.06.7WATER BASED20.04.198931441.6121.04.8WATER BASED02.05.198931541.6220.05.7WATER BASED21.04.198931601.6121.06.7WATER BASED24.04.198931601.6121.06.7WATER BASED02.05.198931641.6118.06.2WATER BASED24.04.198931641.6118.05.7WATER BASED24.04.198931641.6119.05.7WATER BASED26.04.198931701.6122.06.2WATER BASED02.05.198931851.096.05.3WATER BASED22.05.198932471.5823.06.2WATER BASED02.05.198933201.5622.05.3WATER BASED03.05.198933611.5721.07.7WATER BASED08.05.198933611.5722.010.5WATER BASED08.05.198933611.5620.07.7WATER BASED05.05.198933611.5622.07.2WATER BASED05.05.198933841.5721.08.1WATER BASED08.05.198934601.5619.07.7WATER BASED10.05.198934881.5721.07.7WATER BASED10.05.198935171.5917.06.7WATER BASED19.05.198935171.3814.04.3WATER BASED23.05.198935171.3813.03.8WATER BASED24.05.198935171.3812.03.8WATER BASED26.05.198935171.3812.02.9WATER BASED29.05.198935171.3812.02.9WATER BASED29.05.198935171.3812.03.8WATER BASED29.05.198935171.3816.03.8WATER BASED30.05.198935171.4414.03.8WATER BASED31.05.198935171.4414.03.8WATER BASED01.06.198935171.44WATER BASED05.06.198935171.5917.05.7WATER BASED22.05.198935171.3813.0WATER BASED25.05.198935291.5618.08.6WATER BASED11.05.198935741.5922.08.1WATER BASED16.05.198935741.5921.08.6WATER BASED16.05.198935741.5921.08.1WATER BASED16.05.198935741.5921.08.6WATER BASED18.05.198935741.5919.08.1WATER BASED18.05.198935741.5917.07.7WATER BASED18.05.198935741.5719.08.1WATER BASED12.05.1989 -
Palynological slides at the Norwegian Offshore Directorate
Palynological slides at the Norwegian Offshore Directorate Sample depthDepth unitSample typeLaboratory3163.1[m]CHYDRO8880.0[ft]DCSSI8940.0[ft]DCSSI9000.0[ft]DCSSI9060.0[ft]DCSSI9120.0[ft]DCSSI9180.0[ft]DCSSI9240.0[ft]DCSSI9300.0[ft]DCSSI9363.0[ft]SWCSSI9420.0[ft]DCSSI9480.0[ft]DCSSI9540.0[ft]DCSSI9585.0[ft]SWCSSI9600.0[ft]DCSSI9660.0[ft]DCSSI9684.0[ft]SWCSSI9720.0[ft]DCSSI9780.0[ft]DCSSI9840.0[ft]DCSSI9900.0[ft]DCSSI9930.0[ft]DCSSI9960.0[ft]SWCSSI9990.0[ft]SWCSSI10020.0[ft]DCSSI10050.0[ft]DCSSI10080.0[ft]DCSSI10110.0[ft]DCSSI10140.0[ft]DCSSI10170.0[ft]DCSSI10200.0[ft]DCSSI10229.9[ft]CSSI10276.3[ft]CSSI10308.6[ft]CSSI10339.3[ft]CSSI10362.0[ft]CSSI10369.3[ft]CSSI10400.0[ft]DCSSI10460.0[ft]DCSSI10490.0[ft]DCSSI10520.0[ft]DCSSI10580.0[ft]DCSSI10640.0[ft]DCSSI10700.0[ft]DCSSI10744.0[ft]SWCSSI10780.0[ft]DCSSI10810.0[ft]DCSSI10850.0[ft]SWCSSI10880.0[ft]SWCSSI10910.0[ft]DCSSI10940.0[ft]DCSSI10970.0[ft]DCSSI11000.0[ft]DCSSI11030.0[ft]DCSSI11060.0[ft]DCSSI11091.0[ft]SWCSSI