The development of the North Morecambe gas field, East Irish Sea Basin, UK

The North Morecambe Gas Field in the East Irish Sea Basin was discovered by well 110/2-3 in 1976 and contains reserves of over 1TCF. The structure is fault-closed on three sides, and dip-closed to the north. Development is by 10 conventionally deviated high-angle wells, from a not-normally-manned platform, through a dedicated pipeline to a new terminal at Barrow. The Triassic Sherwood Sandstone Group reservoir is composed of sandstones deposited in a semi-arid,fluvial and aeolian setting. Thin, aeolian sandstones dominate flow into the well-bore. Platy illite reduces the permeability by 2-3 orders of magnitude in the lower illite-affected zone of the reservoir. RFT measurements from the first development well proved that the free water level was 25 ft higher than expected, giving a maximum gas column of 975 ft. Re-mapping after drilling has shown that 56% of the GIIP is contained in the high permeability illite-free zone.