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 South Chukchi Basin separates the late Mesozoic Chukotka Fold Belt from the Wrangel Arch and represents the northwestern continuation of the Hope Basin of the United States sector of the Chukchi Sea, which is filled with middle Eocene–Quaternary nonmarine, marine, and lacustrine rocks. The main stages of South Chukchi Basin development in the Cenozoic are comparable to those of the Hope Basin, although the analysis of onshore data from Chukotka and Wrangel Island points to the beginning of sedimentation during the Aptian–Albian–Late Cretaceous. In the South Chukchi Basin, the sediment thickness seldom exceeds 3 to 4 km (1.9–2.5 mi)but can locally reach 5to 6 km(3.1–3.7 mi).The geometry of the faults indicates an extensional and/or transtensional setting for the South Chukchi Basin, although folds, reverse and thrust faults, pop-up and positive flower structures also occur, pointing to the local development of compressional and transpressional stress. Low-angle thrust faults predating the Aptian(?)–Paleogene extension (most likely of Late Jurassic–Neocomian age) are recognized at the base of the South Chukchi Basin. This could support the idea that the extension in the basin was driven by gravitational collapse of the Wrangel-Herald-Lisburne fold and thrust belt in the post-Neocomian. Based on the interpretation of new seismic data and analysis of published material, we believe that the hydrocarbon potential of the South Chukchi Basin may be significantly higher than what has been previously suggested.

Abstract Organic-rich shale contains significant amounts of gas held within fractures and micropores and adsorbed onto organic matter. In the USA shale gas extracted from regionally extensive units such as the Barnett Shale currently accounts for 6% of gas production and is likely to reach 30% by 2015. Shale gas prospectivity is controlled by the amount and type of organic matter held in the shale, its thermal maturity, burial history, microporosity and fracture spacing and orientation. Potential targets range in age from Cambrian to the late Jurassic, within the main UK organic-rich black shales: younger shales have been excluded because they have not reached the gas window, but they may possess a biogenic gas play. A geographic information system, showing the distribution of potential reservoir units, has been created combining information on hydrocarbon shows, thermal maturity, fracture orientation, gas composition, and isotope data to identify potentially prospective areas for shale gas. Some of these data are shown as graphs and maps, but crucial data is lacking because earlier exploration concentrated on conventional reservoirs. The prospects include Lower Palaeozoic shale basins on the Midland Microcraton (a high risk because no conventional gas has been proved in this play), Mississippian shales in the Pennine Basin (the best prospect associated with conventional fields and high maturity), Pennsylvanian shales in the Stainmore and Northumberland Basin system (high risk because no conventional gas discoveries exist) and Jurassic shales in Wessex and Weald basins (small conventional fields signify potential here).