Abstract The Elswick Field is located within Exploration Licence EXL 269a (Cuadrilla Resources Ltd is the operator) on the Fylde peninsula, West Lancashire, UK. It is the first producing onshore gas field to be developed by hydraulic fracture stimulation in the region. Production from the single well field started in 1996 and has produced over 0.5 bcf for onsite electricity generation. Geologically, the field lies within a Tertiary domal structure within the Elswick Graben, Bowland Basin. The reservoir is the Permian Collyhurst Sandstone Formation: tight, low-porosity fluvial desert sandstones, alluvial fan conglomerates and argillaceous sandstones. The reservoir quality is primarily controlled by depositional processes further reduced by diagenesis. Depth to the reservoir is 3331 ft TVDSS with the gas–water contact at 3400 ft TVDSS and with a net pay thickness of 38 ft.

Abstract The Lennox Field is a saturated oilfield with a significant primary gas cap at initial conditions. Located in the East Irish Sea withincBlocks 110/14c and 110/15a, the field was discovered in 1992. First oil was achieved in February 1996. Lennox is a rollover anticline structure. The Triassic Ormskirk Sandstone Formation reservoir comprises good-quality aeolian and fluvial sandstones with typicalcporosities of 11–21%. The gas column reaches a height of c. 850 ft and overlays a 143 ft oil column. Oil initially-in-place is estimated to be 202 MMbbl, whilst total gas initially-in-place is 521 bcf. The field has been developed by a wellhead platform tied-back to the neighbouring Douglas Complex. The field development has been split into two phases: the first phase focused on oil production and involved the drilling of 12 horizontal and multilateral production wells and two gas injection wells. Oil production ceased in 2012 with total produced volumes of 103 MMbbl. The second phase comprised the gas cap blowdown, and the optimization of the existing well stock for gas production. Eni UK acquired the operatorship of the field in April 2014 and has focused on maximizing and accelerating gas production from the field.

Abstract Salt mining along with natural and human-induced salt dissolution affects the ground over Permian and Triassic strata in the UK. In England, subsidence caused by salt mining, brine extraction and natural dissolution is known to have occurred in parts of Cheshire (including Northwich, Nantwich, Middlewich), Stafford, Blackpool, Preesall, Droitwich and Teeside/Middlesbrough; it also occurs around Carrickfergus in Northern Ireland. Subsidence ranges from rapid and catastrophic failure to gentle sagging of the ground, both forms being problematical for development, drainage and the installation of assets and infrastructure such as ground source heat pumps. This paper reviews the areas affected by salt subsidence and details the mitigation measures that have been used; the implications for planning in such areas are also considered.

Abstract Hydrocarbon exploration in the East Irish Sea Basin began with the identification of surface oil seeps in peat beds in Lancashire, UK. This precipitated the drilling of the first onshore exploration wells. The discovery of the Formby Field in west Lancashire at the end of the 1930s triggered a wave of further drilling. Wells drilled in west Lancashire had limited success, with only minor hydrocarbon shows, whilst the production from the Formby Field was modest. Nonetheless, the invaluable geological information taken from onshore wells and the ratification of the Continental Shelf Act led to a shift in focus to the offshore and a period of significant interest in the East Irish Sea. Two key periods of oil and gas exploration activity stand out in the history of the offshore basin, the first headed by the Gas Council during the 1970s resulted in the discovery of the gas giants of Morecambe Bay, whilst the second fronted by Hamilton Oil during the 1990s heralded the discovery of oil with the Douglas and Lennox fields in Liverpool Bay. Exploration in the basin has waned during the last decade; however, to date, this mature hydrocarbon province has yielded estimated hydrocarbon reserves of over 1.8 BBOE (billion barrels of oil equivalent).