34/7-28
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General information
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Wellbore history
GeneralWell 34/7-28 is located in the Tampen area in the Northern North Sea. It was drilled on a prospect situated north east of the Statfjord Nord field and east of the Snorre field. The well tested the NW III prospect, which was defined as a stratigraphic trap with pinch out of the Draupne Formation. The sands in the Draupne Formation were expected to be erosional products from the Snorre block positioned in a north east direction of the well.Operations and resultsWildcat well 34/7-28 was spudded with the semi-submersible installation Transocean Leader on 30 December 1997. The well was initially drilled to a total depth of 1267 m in the 12 l/4" section where the decision was made to plug and abandon the well. The abandonment was due to concerns over the integrity of the 18 3/4" wellhead housing, which had suffered damage during BOP latching procedures. At this time a total of 24.9 days had been spent on the well. With the rig moved ca. 25 m NNE from the original location, well 34/7-28 was re-spudded on 24 January 1998 and drilled to TD at 3005 m in the Middle Jurassic Drake Formation. The final 34/7-28 well was drilled with sea water and bentonite hi-vis sweeps down to 1300 m, with silicate mud from 1300 m to 2165 m, and with KCl/glycol mud ("Aqaucol D" polypropylene glycols) from 2165 m to TD.Apart from the Utsira Formation only traces of sand was penetrated above top Jurassic. Sandstones were encountered in the prospective level of the Viking Group. The uppermost sand at 2666 m was a 3 m thick Intra Draupne Formation sandstone overlying 10 m of Heather Formation shale. The lower sand at 2679 m was a 16 m thick Intra Heather Formation sandstone, interpreted as a gravitation deposit. Both sandstones were penetrated at shallower depth than the oil-water contact in Statfjord Nord and both were water filled. An undifferentiated sequence of water filled Rannoch/Etive Formations sandstones was penetrated from 2805 to 2972 m. Pressure measurements showed that the sands in the Viking group were in communication, but they were not in communication with the sands in the Brent Group. From this it was concluded that the base seal was intact, and the fault to the south west was sealing. Weak shows were described in the core from the Intra Heather Formation sandstone, but subsequent geochemical analyses in the laboratory were not able to confirm this. This was the only indication of hydrocarbons in the well.Two cores were cut in the Intra Heather Formation sandstone and Heather Formation shale from 2668-2694 m and 2694-2726.5 m. The sands were massive and had good visible porosity. MDT pressure tests were carried out in the Viking Group and in the Brent Group. No fluid sampling was attempted.The well was permanently abandoned on 3 March 1998 as a dry well.TestingNo drill stem test was performed. -
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]1310.002924.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom12668.02692.7[m ]22694.02725.0[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]55.7Cores 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 typeCONDUCTOR30376.036380.00.00LOTSURF.COND.13 3/81293.017 1/21295.01.69LOTINTERM.9 5/82154.012 1/42155.01.78LOTOPEN HOLE3005.08 1/23005.00.00LOT -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CST GR26533000FMI DSI NGT21543005MDT GR26672957MWD - DIR328379MWD - GR RES DIR3793005PEX HALS21543005VSP14103000 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit328112011281683168316911865186521092654265426582666266626692679269527922792280529722972 -
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]pdf35.23 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured13001.3713.0WATER BASED19641.5918.0WATER BASED21651.5921.0WATER BASED24251.5834.0WATER BASED26921.5832.0WATER BASED27111.5829.0WATER BASED30051.58WATER BASED -
Palynological slides at the Norwegian Offshore Directorate
Palynological slides at the Norwegian Offshore Directorate Sample depthDepth unitSample typeLaboratory1330.0[m]DCUOS1370.0[m]DCUOS1410.0[m]DCUOS1450.0[m]DCUOS1490.0[m]DCUOS1530.0[m]DCUOS1570.0[m]DCUOS1610.0[m]DCUOS1650.0[m]DCUOS1690.0[m]DCUOS1730.0[m]DCUOS1770.0[m]DCUOS1810.0[m]DCUOS1850.0[m]DCUOS1880.0[m]DCUOS1900.0[m]DCUOS1920.0[m]DCUOS1940.0[m]DCUOS1960.0[m]DCUOS1980.0[m]DCUOS2000.0[m]DCUOS2020.0[m]DCUOS2040.0[m]DCUOS2065.0[m]DCUOS2080.0[m]DCUOS2100.0[m]DCUOS2120.0[m]DCUOS2140.0[m]DCUOS2155.0[m]DCUOS2180.0[m]DCUOS2200.0[m]DCUOS2220.0[m]DCUOS2240.0[m]DCUOS2260.0[m]DCUOS2280.0[m]DCUOS2295.0[m]DCUOS2320.0[m]DCUOS2340.0[m]DCUOS2360.0[m]DCUOS2380.0[m]DCUOS2400.0[m]DCUOS2420.0[m]DCUOS2440.0[m]DCUOS2460.0[m]DCUOS2480.0[m]DCUOS2500.0[m]DCUOS2520.0[m]DCUOS2540.0[m]DCUOS2555.0[m]DCUOS2580.0[m]DCUOS2600.0[m]DCUOS2620.0[m]DCUOS2640.0[m]DCUOS2660.0[m]DCUOS2668.0[m]CNETW2669.0[m]CNETW2670.0[m]CNETW2671.0[m]CNETW2672.0[m]CNETW2673.0[m]CNETW2674.0[m]CNETW2675.0[m]CNETW2676.0[m]CNETW2677.0[m]CNETW2679.0[m]CNETW2680.0[m]CNETW2681.0[m]CNETW2684.0[m]CNETW2686.0[m]CNETW2687.0[m]CNETW2688.0[m]CNETW2690.0[m]CNETW2691.0[m]CNETW2692.0[m]CNETW2694.0[m]CNETW2695.0[m]CNETW2696.0[m]DCNETW2697.0[m]DCNETW2698.0[m]DCNETW2703.0[m]DCNETW2704.0[m]DCNETW2706.0[m]DCNETW2707.0[m]DCNETW2709.0[m]DCNETW2711.0[m]DCNETW2712.0[m]CNETW2713.0[m]CNETW2715.0[m]CNETW2716.0[m]CNETW2717.0[m]CNETW2718.0[m]CNETW2721.0[m]CNETW2722.0[m]CNETW2723.0[m]CNETW2724.0[m]CNETW2726.0[m]DCUOS2735.0[m]DCUOS2744.0[m]DCUOS2750.0[m]DCUOS2759.0[m]DCUOS2768.0[m]DCUOS2777.0[m]DCUOS2786.0[m]DCUOS2792.0[m]DCUOS2801.0[m]DCUOS2807.0[m]DCUOS2816.0[m]DCUOS2825.0[m]DCUOS2834.0[m]DCUOS2843.0[m]DCUOS2852.0[m]DCUOS2861.0[m]DCUOS2870.0[m]DCUOS2888.0[m]DCUOS2897.0[m]DCUOS2906.0[m]DCUOS2915.0[m]DCUOS2924.0[m]DCUOS2933.0[m]DCUOS2942.0[m]DCUOS2951.0[m]DCUOS2960.0[m]DCUOS2969.0[m]DCUOS2978.0[m]DCUOS2987.0[m]DCUOS2996.0[m]DCUOS3005.0[m]DCUOS