The West Sole Field, Block 48/6, UK North Sea

Abstract West Sole is located in the Sole Pit area of the Southern North Sea Permian Basin in UK Block 48/6. The field was discovered in 1965 and was the first commercial discovery in the UK Continental Shelf. Gas Production commenced in 1967. Initial reserves are 1.873 TCF of which 1.335 TCF had been produced by the end of 1989. Gas is trapped in aeolian sandstones of the Permian Lower Leman Sandstone Formation. Three depositional facies are recognized, comprising aeolian dune, fluvial and sabkha. The aeolian dune facies form the principal reservoir sandstones, in units up to 40 m (131 ft) thick. However, permeability is reduced due to pervasive illite cementation, such that it averages 3 md in the dune sandstones. Productivity is enhanced in the southern part of the field by 'open' gas-filled fractures, generated during the Alpine inversion. The trap was also amplified at this stage and comprises a faulted inversion anticline trending NW-SE. The source rock is the Westphalian Coal Measures, lying directly beneath the reservoir.