3/7-4
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General information
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Wellbore history
GeneralWell 3/7-4 was designed to drill a prospect on the Lulita culmination. The Lulita prospect extends in to Danish waters, and forms part of an elongated, N-S trending, salt induced feature on the western margin of the Søgne Basin. The present structural features were developed during mid Cretaceous time, and closure at Late Cretaceous and Tertiary levels essentially reflects compaction and drape over the Jurassic high. The Jurassic Lulita closure is separated from the area tested by the 3/7-3 well by a faulted saddle, which also is well expressed at Tertiary and Cretaceous levels, providing a vertical closure of some 75 metres. The well had as primary objective to test the hydrocarbon potential of Middle Jurassic sandstones within a structural/stratigraphic trap, and as secondary objective to testing the potential in possible Late Jurassic and Early Cretaceous sandstones, within a structural trap. Additional objectives included testing of Late Cretaceous Chalk, found hydrocarbon bearing in the nearby Harald field, Paleocene/Eocene turbiditic sandstones, and the reservoir quality of the Triassic sequence. The well should drill some 150 m into rocks of Triassic age. Shallow gas could be encountered at 317 to 388 m, at 485, and at 515 m according to seismic anomalies.Operations and resultsWildcat well 3/7-4 was spudded with the semi-submersible installation Hunter on 20 September 1989 and drilled to TD at 3723 m in the Permian Zechstein Group. At 3472.9 m the string was backed off, and a cement kick off plug was set. The hole was sidetracked from 3405 m. The well was drilled with seawater and hi-vis spud mud down to 622 m, with KCl polymer from 622 m to 3473 m, and with seawater/polymer from 3473 m to TD. No shallow gas was encountered.A 160 m hydrocarbon column from top Ula Formation and down to 3572 m in the Bryne Formation was found from well-logs, core shows, and RFT pressure gradients. Strong shows were recorded throughout the reservoir. Below the ODT shows died out, and were not seen below 3600 m. The RFT pressures indicated a light condensate-type fluid gradient of 0.39 bar/10m in the hydrocarbon-bearing zone. The secondary and additional objective levels were evaluated: A 29 m thick sequence of Maureen Formation sandstone was encountered in the Tertiary, no reservoir quality sands or chalk was found in the Late Jurassic and Cretaceous, and the Triassic was missing. Weak shows were recorded in the Maureen sandstone.Two segregated RFT fluid samples were obtained. The first (No. 1) from 3564.5 m contained gas, condensate and water, whilst the second (No. 2) from 3442.5 m contained gas and water only. A total of 123.5 m conventional core was recovered in eight cores in the interval 3416 m to 3574 in the Ula and Bryne Formations. Core no 1 was cut in the first hole, the remaining seven cores were cut in the sidetrack.The well was permanently abandoned on 23 January 1990 as a gas/condensate discovery.TestingTwo DST tests were performed in this well. Test no 1A in the interval 3473 to 3537 m produced 665 Sm3/d liquid hydrocarbons of 0.804 g/cm3 and 884450 Sm3 gas through a 19 mm choke. The Gas/Liquid ratio was 1330 Sm3/Sm3. Test no 1B in the interval 3440 to 3537 m produced 611 Sm3/d of 0.796 g/cm3 liquid and 838292 Sm3 gas through a 19 mm choke. The GLR was 1372 Sm3/Sm3. The gas gravity (air = 1) was 0.72 in both tests. Temperature measurements during the tests gave a reservoir temperature of 131 deg C. -
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]630.003721.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom13416.03436.0[m ]23437.03464.7[m ]33464.43487.9[m ]43492.03501.2[m ]53504.03514.0[m ]63514.03520.0[m ]73526.03553.4[m ]83553.43574.3[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]144.7Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
Core photos
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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 availableDSTDST1A3440.003537.0001.01.1990 - 00:00YESDSTDST1B3470.003440.0003.01.1990 - 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 typeCONDUCTOR30177.036187.00.00LOTINTERM.20610.026622.01.86LOTINTERM.20611.026622.01.86LOTINTERM.13 3/82093.017 1/22110.01.88LOTINTERM.9 5/83383.012 1/43603.01.95LOTLINER73710.08 3/83723.00.00LOT -
Drill stem tests (DST)
Drill stem tests (DST) Test numberFrom depth MD
[m]To depth MD
[m]Choke size
[mm]1.03473353719.02.03440347319.0Drill stem tests (DST) Test numberFinal shut-in pressure
[MPa]Final flow pressure
[MPa]Bottom hole pressure
[MPa]Downhole temperature
[°C]1.01312.0131Drill stem tests (DST) Test numberOil
[Sm3/day]Gas
[Sm3/day]Oil density
[g/cm3]Gas grav. rel.airGOR
[m3/m3]1.06658844500.8040.72013302.06118382920.7960.7201372 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CBL VDL CCL GR922092CBL VDL CCL GR18902400CBL VDL CCL GR31863636CDL CNL SPL CAL33703723CND CNL DISL GR CAL5752103CND CNL SPL CAL20923470DIFL AC GR180619DIFL AC SP GR20703502DIFL AC SP GR33823722DIFL AC SP GR CAL5452108DIPLOG GR31503469DIPLOG GR33933722DLL MLL CAL GR33823721DLL MLL GR20913470FMT GR28253260FMT GR34153684FMT GR34433443GYRO MULTISHOT922055GYRO MULTISHOT20553640MWD - GR RES DIR1873603PLT GR34303549SWS GR6272088SWS GR34043707VSP27003723 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit911412274727472766278728192848284829223088324732473255326132613411341134743688 -
Geochemical information
Geochemical information Document nameDocument formatDocument size [MB]pdf5.53 -
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]pdf48.76 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured1871.07WATER BASED3461.07WATER BASED6221.3250.0WATER BASED10111.3454.0WATER BASED11821.3356.0WATER BASED13631.3353.0WATER BASED16491.3365.0WATER BASED21101.5062.0WATER BASED24501.5053.0WATER BASED28891.5253.0WATER BASED30681.5045.0WATER BASED32561.5240.0WATER BASED33901.5646.0WATER BASED34051.5548.0WATER BASED34161.5538.0WATER BASED35061.5540.0WATER BASED35711.5540.0WATER BASED37231.5353.0WATER BASED37251.5448.0WATER BASED -
Palynological slides at the Norwegian Offshore Directorate
Palynological slides at the Norwegian Offshore Directorate Sample depthDepth unitSample typeLaboratory1980.0[m]DCRRI1980.0[m]DCAMOCO2010.0[m]DCRRI2010.0[m]DCAMOCO2040.0[m]DCRRI2040.0[m]DCAMOCO2070.0[m]DCRRI2070.0[m]DCAMOCO2080.0[m]DCRRI2090.0[m]DCRRI2100.0[m]DCRRI2100.0[m]DCAMOCO2120.0[m]DCRRI2130.0[m]DCRRI2130.0[m]DCAMOCO2140.0[m]DCRRI2160.0[m]DCRRI2160.0[m]DCAMOCO2170.0[m]DCRRI2180.0[m]DCRRI2190.0[m]DCRRI2190.0[m]DCAMOCO2200.0[m]DCRRI2210.0[m]DCRRI2220.0[m]DCRRI2220.0[m]DCAMOCO2240.0[m]DCRRI2250.0[m]DCRRI2250.0[m]DCAMOCO2260.0[m]DCRRI2280.0[m]DCRRI2280.0[m]DCAMOCO2290.0[m]DCRRI2300.0[m]DCRRI2310.0[m]DCRRI2310.0[m]DCAMOCO2320.0[m]DCRRI2330.0[m]DCRRI2340.0[m]DCRRI2340.0[m]DCAMOCO2360.0[m]DCRRI2370.0[m]DCRRI2370.0[m]DCAMOCO2380.0[m]DCRRI2400.0[m]DCRRI2400.0[m]DCRRI2400.0[m]DCRRI2410.0[m]DCRRI2420.0[m]DCRRI2430.0[m]DCRRI2430.0[m]DCAMOCO2440.0[m]DCRRI2450.0[m]DCRRI2460.0[m]DCRRI2460.0[m]DCAMOCO2480.0[m]DCRRI2490.0[m]DCRRI2490.0[m]DCAMOCO2500.0[m]DCRRI2520.0[m]DCRRI2520.0[m]DCAMOCO2540.0[m]DCRRI2550.0[m]DCRRI2550.0[m]DCAMOCO2560.0[m]DCRRI2570.0[m]DCRRI2580.0[m]DCRRI2580.0[m]DCAMOCO2600.0[m]DCRRI2610.0[m]DCRRI2610.0[m]DCAMOCO2620.0[m]DCRRI2640.0[m]DCRRI2640.0[m]DCAMOCO2650.0[m]DCRRI2660.0[m]DCRRI2670.0[m]DCRRI2670.0[m]DCAMOCO2680.0[m]DCRRI2690.0[m]DCRRI2700.0[m]DCRRI2700.0[m]DCAMOCO2710.0[m]DCRRI2720.0[m]DCRRI2730.0[m]DCRRI2740.0[m]DCRRI2750.0[m]DCRRI2760.0[m]DCRRI2770.0[m]DCRRI2780.0[m]DCRRI2780.0[m]DCRRI2790.0[m]DCRRI2790.0[m]DCAMOCO2800.0[m]DCRRI2800.0[m]DCAMOCO2810.0[m]DCRRI2810.0[m]DCAMOCO2820.0[m]DCRRI2820.0[m]DCAMOCO2830.0[m]DCRRI2830.0[m]DCAMOCO2840.0[m]DCRRI2840.0[m]DCAMOCO2850.0[m]DCRRI2850.0[m]DCAMOCO2860.0[m]DCRRI2860.0[m]DCAMOCO2880.0[m]DCRRI2890.0[m]DCRRI2900.0[m]DCRRI2920.0[m]DCRRI2930.0[m]DCRRI2940.0[m]DCRRI2960.0[m]DCRRI2970.0[m]DCRRI2980.0[m]DCRRI3000.0[m]DCRRI3382.2[m]CAPT3417.0[m]CAPT3426.0[m]CAPT3428.0[m]CAPT3430.0[m]CAPT3432.0[m]CAPT3434.0[m]CAPT3436.0[m]CAPT3438.0[m]CAPT3440.0[m]CAPT3440.9[m]CAPT3441.9[m]CAPT3442.3[m]CAPT3446.4[m]CAPT3447.1[m]CAPT3447.9[m]CAPT3448.2[m]CAPT3448.2[m]CAPT3450.5[m]CAPT3451.8[m]CAPT3459.2[m]CAPT3459.4[m]CAPT3459.5[m]CAPT3463.4[m]CAPT3464.4[m]CAPT3466.0[m]CAPT3467.8[m]CAPT3469.0[m]CAPT3469.3[m]CAPT3471.0[m]CAPT3471.8[m]CAPT3473.4[m]CAPT3475.8[m]CAPT3476.0[m]CAPT3480.8[m]CAPT3486.5[m]CAPT3495.5[m]CAPT3497.8[m]CAPT3498.4[m]CAPT3507.5[m]CAPT3509.1[m]CAPT3511.2[m]CAPT3513.1[m]CAPT3514.8[m]CAPT3516.8[m]CAPT3519.4[m]CAPT3522.6[m]CAPT3527.7[m]CAPT3534.0[m]CAPT3539.7[m]CAPT3541.3[m]CAPT3551.6[m]CAPT3552.5[m]CAPT3554.0[m]CAPT3554.0[m]CAPT3558.5[m]CAPT3559.5[m]CAPT3563.0[m]CAPT3563.5[m]CAPT3568.0[m]CAPT3568.0[m]CAPT3568.2[m]CAPT3574.3[m]CAPT