6406/2-3
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General information
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Wellbore history
GeneralThe main objective of well 6406/2-3 was to test the hydrocarbon potential of the Kristin structure with respect to Middle and Lower Jurassic sandstones, and to test the reservoir qualities at great depths (prognosed TD 5600 m). The secondary target for the well was the seismically prognosed Aptian sandstone, which was interpreted to form either a stratigraphic trap or a structural closure above the crest of the Kristin structure. The Kristin structure is a fault bounded horst block, somewhat eroded in the western part, with only minor internal faulting. The Kristin structure extends into PL 134 area, and the well location was agreed between PL 199 and PL 134. PL 134 contributed with 20% of the expenses to the joint well. Hydrocarbon leakage due to the prognosed high pore pressure in the Kristin structure was regarded the primary risk for the trap, knowing that all high pressured wells drilled in this area had been dry.Operations and resultsWildcat well 6406/2-3 was spudded 24 August 1996 with the semi-submersible rig "Transocean Arctic", and reached TD 47 m into the Åre Formation at 5258 m on 26 January 1997. Due to well control problems starting 23 September a technical side-track was started 23 October from the 13 3/8" casing shoe at 2834 m, and the suffix T2 was added to the well designation (6406/2-3T2). During intermediate logging in 8 1/2" section a FMT tool got stuck, and a second sidetrack had to be done from the 9 5/8" casing shoe at 4538 m. The second sidetrack, 6406/2-3T3, was started 6 December 1996. Shallow gas caused no operational problems. The well was drilled with seawater swept with high viscosity mud down to 1413 m. ANCO 2000 water based mud with ANCO 208 glycol additive was used from 1413 to 2848 m, while ANCOVERT oil based mud was used from 2848 m to TD.
The main result of well 6406/2-3 was the discovery of gas/condensate in Garn and Ile Formations as proven by production tests, fluid samples, cores and logs. Both Garn and Ile Formations were filled with gas/condensate throughout the units in the well position. Tofte, Tilje and Åre Formations were water bearing, except for a possible hydrocarbon-water transition zone in the uppermost parts of the Tofte Formation. The prognosed Lower Cretaceous Aptian sandstone was not encountered in the well. The well also penetrated Cretaceous sandstones (Lysing and Lange sandstones) that were interpreted to be water bearing with some shows and with poor reservoir qualities.
Reservoir qualities of the Middle Jurassic sandstones of the Garn and Ile Formations are in general very good, ranging from fair to excellent. The reservoir properties of the Garn Formation are best in the upper part, with porosities up to 20% and permeabilities up to 1 Darcy. The properties of the Ile Formation are best in the lower part and in one central zone of the unit, with porosities up to 30% and permeabilities up to 12 Darcy. The reservoir qualities of the Tofte, Tilje and Åre Formations are more variable, with Tofte Formation ranging from fair to good, Tilje Formation ranging from poor to good, and Åre Formation having poor reservoir qualities.
Pore pressures of the Jurassic units were very high, reaching a maximum gradient of 1.97 g/cc EMW in upper part of the Garn Formation.
Ten cores were cut from Lange, Garn, Ile, Tofte and Tilje Formations, totaling 202.95 m, with a recovery of 198.35 m. Two cores were cut in the Cretaceous Lange Formation. Fluid samples containing gas and condensate were collected in the Garn and Ile Formations, whilst water samples were collected in the Tofte, Tilje and Åre Formations. The well was plugged and abandoned as a gas/condensate discovery.TestingTwo zones in the well were successfully production tested. Test # 1 in lower Ile Formation (4806 - 4832 m) produced 892 000 Sm3/D gas and 890 Sm3/D condensate (GOR: 1003 Sm3/Sm3). Test # 2 in upper Garn Formation (4629 - 4654.4 m) produced 777 000 Sm3/D gas and 1048 Sm3/D condensate (GOR: 744 Sm3/Sm3). -
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]1420.005256.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom14380.04401.5[m ]24402.04425.5[m ]34633.04639.0[m ]44642.04650.8[m ]54651.54661.5[m ]64661.54671.0[m ]74671.04699.4[m ]84699.34727.8[m ]94754.04777.5[m ]104777.54806.1[m ]114898.04925.4[m ]125038.05064.9[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]242.6Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
Core photos
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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 typeCONDUCTOR30482.036484.00.00LOTINTERM.18 5/81405.0201407.01.80LOTINTERM.13 3/82834.017 1/22835.01.96LOTINTERM.9 5/84538.012 1/44540.02.20LOTLINER75258.08 1/25258.00.00LOT -
Drill stem tests (DST)
Drill stem tests (DST) Test numberFrom depth MD
[m]To depth MD
[m]Choke size
[mm]1.04832480617.02.04654462917.5Drill stem tests (DST) Test numberFinal shut-in pressure
[MPa]Final flow pressure
[MPa]Bottom hole pressure
[MPa]Downhole temperature
[°C]1.090.00089.00091.0001672.088.00081.00089.000166Drill stem tests (DST) Test numberOil
[Sm3/day]Gas
[Sm3/day]Oil density
[g/cm3]Gas grav. rel.airGOR
[m3/m3]1.08908920000.7910.72010032.010487770000.7920.720744 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]DPIL MAC DSL45374928DPIL MAC GR28334545DPIL MAC GR48755255DPIL MAC ZDL GR14052845DPIL ZDL GR45124654FMT GR34304405FMT GR46265257HEXDIP CBIL GR45375243MRIL GR45505255MWD - DIR395487MWD - GR RES DIR4875258RCOR GR34304504SWC GR45784957ZDL CN DSL45375257ZDL CN GR28334926 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit39639615181954195423002300236424252425254928383429342934404620462946294716475148374837487750285210 -
Composite logs
Composite logs Document nameDocument formatDocument size [MB]pdf0.77 -
Geochemical information
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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]pdf11.09pdf47.22 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured6801.0316.0SPUD MUD9001.0316.0SPUD MUD14131.2018.0SPUD MUD15491.3020.0KCL MUD20601.4527.0KCL MUD25251.7238.0KCL MUD25701.7246.0KCL MUD28481.7244.0KCL MUD28601.8253.0OIL BASED28721.8251.0OIL BASED31701.8047.0OIL BASED33891.5044.0OIL BASED34901.8045.0OIL BASED35801.5741.0OIL BASED35911.8043.0OIL BASED36891.5747.0OIL BASED37531.8041.0OIL BASED38021.8253.0OIL BASED39711.6455.0OIL BASED39751.6754.0OIL BASED40171.6750.0OIL BASED40501.6745.0OIL BASED40541.6755.0OIL BASED40701.6744.0OIL BASED40801.8047.0OIL BASED40871.8143.0OIL BASED41801.7854.0OIL BASED42761.8045.0OIL BASED43781.8050.0OIL BASED44021.8051.0OIL BASED44241.8050.0OIL BASED44481.8148.0OIL BASED44601.7854.0OIL BASED45271.8150.0OIL BASED45501.8148.0OIL BASED45541.8952.0OIL BASED45802.0066.0OIL BASED45931.8255.0OIL BASED45961.8267.0OIL BASED45972.0061.0OIL BASED45982.0064.0OIL BASED46032.0065.0OIL BASED46142.0066.0OIL BASED46262.0680.0OIL BASED46322.0064.0OIL BASED46342.0059.0OIL BASED46352.0069.0OIL BASED46612.0057.0OIL BASED46622.0665.0OIL BASED46712.0669.0OIL BASED46992.0662.0OIL BASED47192.0665.0OIL BASED47282.0666.0OIL BASED47422.0665.0OIL BASED47542.0665.0OIL BASED47772.0666.0OIL BASED47782.0666.0OIL BASED48062.0666.0OIL BASED48062.0665.0OIL BASED48432.0664.0OIL BASED48972.0667.0OIL BASED49262.0665.0OIL BASED49762.0663.0OIL BASED50002.0664.0OIL BASED50202.0663.0OIL BASED50382.0665.0OIL BASED50632.0663.0OIL BASED50662.0665.0OIL BASED50812.0663.0OIL BASED51232.0663.0OIL BASED51692.0671.0OIL BASED52582.0666.0OIL BASED52582.0676.0OIL BASED -
Palynological slides at the Norwegian Offshore Directorate
Palynological slides at the Norwegian Offshore Directorate Sample depthDepth unitSample typeLaboratory1430.0[m]DCSTRAT1450.0[m]DCSTRAT1470.0[m]DCSTRAT1490.0[m]DCSTRAT1510.0[m]DCSTRAT1530.0[m]DCSTRAT1550.0[m]DCSTRAT1570.0[m]DCSTRAT1590.0[m]DCSTRAT1610.0[m]DCSTRAT1630.0[m]DCSTRAT1650.0[m]DCSTRAT1670.0[m]DCSTRAT1690.0[m]DCSTRAT1710.0[m]DCSTRAT1730.0[m]DCSTRAT1750.0[m]DCSTRAT1770.0[m]DCSTRAT1790.0[m]DCSTRAT1810.0[m]DCSTRAT1830.0[m]DCSTRAT1850.0[m]DCSTRAT1870.0[m]DCSTRAT1890.0[m]DCSTRAT1910.0[m]DCSTRAT1930.0[m]DCSTRAT1950.0[m]DCSTRAT1970.0[m]DCSTRAT1990.0[m]DCSTRAT2010.0[m]DCSTRAT2030.0[m]DCSTRAT2050.0[m]DCSTRAT2070.0[m]DCSTRAT2090.0[m]DCSTRAT2110.0[m]DCSTRAT2130.0[m]DCSTRAT2150.0[m]DCSTRAT2170.0[m]DCSTRAT2270.0[m]DCSTRAT2290.0[m]DCSTRAT2310.0[m]DCSTRAT2330.0[m]DCSTRAT2350.0[m]DCSTRAT2370.0[m]DCSTRAT2410.0[m]DCSTRAT2430.0[m]DCSTRAT2470.0[m]DCSTRAT2510.0[m]DCSTRAT2530.0[m]DCSTRAT2550.0[m]DCSTRAT2570.0[m]DCSTRAT2590.0[m]DCSTRAT2610.0[m]DCSTRAT2630.0[m]DCSTRAT2650.0[m]DCSTRAT2670.0[m]DCSTRAT2690.0[m]DCSTRAT2710.0[m]DCSTRAT2730.0[m]DCSTRAT2750.0[m]DCSTRAT2770.0[m]DCSTRAT2790.0[m]DCSTRAT2810.0[m]DCSTRAT2830.0[m]DCSTRAT2850.0[m]DCSTRAT2870.0[m]DCSTRAT2900.0[m]DCSTRAT3000.0[m]DCSTRAT3100.0[m]DCSTRAT3200.0[m]DCSTRAT3300.0[m]DCSTRAT3400.0[m]DCSTRAT3500.0[m]DCSTRAT3600.0[m]DCSTRAT3700.0[m]DCSTRAT3800.0[m]DCSTRAT3900.0[m]DCSTRAT4000.0[m]DCSTRAT4099.0[m]DCSTRAT4201.0[m]DCSTRAT4300.0[m]DCSTRAT4399.0[m]DCSTRAT4501.0[m]DCSTRAT4575.0[m]DCSTRAT4635.0[m]DCSTRAT