Abstract The Elgin, Franklin, Glenelg and West Franklin fields lie approximately 240 km (150 miles) east of Aberdeen in Blocks 22/30b, 22/30c, 29/4d, 29/5b and 29/5c of the UK Central Graben. Franklin was discovered in 1985, Elgin in 1991, Glenelg in 1999 and West Franklin in 2003. Elgin is a complex faulted anticline comprising four panels, while the others are simpler, tilted fault block structures. The main reservoir is the Upper Jurassic Fulmar Formation shoreface sandstone, although the Middle Jurassic Pentland and Triassic Skagerrak formations have also been produced on Franklin. Initial pressure was c. 1100 bar (16 000 psi), with a reservoir temperature of around 190°C (375°F). Production wells are drilled from four wellhead platforms; all connected to a central process, utilities and quarters facility above Elgin. Gas and condensate production started in 2001 from six wells on each of Elgin and Franklin, with the plateau being extended by satellite and infill wells. The project remains the world's largest high-pressure–high-temperature development, requiring continued innovations in geoscience, drilling, completion and operations. Cumulative production at end 2017 is 886 Mboe, with estimated ultimate recovery around 1300 Mboe.

Abstract The Elgin–Franklin complex contains gas condensates in Upper Jurassic reservoirs in the North Sea Central Graben. Upper parts of the reservoirs contain bitumens, which previous studies have suggested were formed by the thermal cracking of oil as the reservoirs experienced temperatures of >150°C during rapid Plio-Pleistocene subsidence. Bitumen-stained cores contaminated by oil-based drilling muds have been analysed by hydropyrolysis. Asphaltene-bound aliphatic hydrocarbon fractions were dominated by n -hexadecane and n -octadecane originating from fatty acid additives in the muds. Uncontaminated asphaltene-bound aromatic hydrocarbon fractions, however, contained a PAH distribution very similar to normal North Sea oils, suggesting that the bitumens may not have been derived from oil cracking. 1D basin models of well 29/5b-6 and a pseudo-well east of the Elgin–Franklin complex utilize a thermal history derived from the basin's rifting and subsidence histories, combined with the conservation of energy currently not contained in the thermal histories. Vitrinite reflectance values predicted by the conventional kinetic models do not match the measured data. Using the pressure-dependent PresRo ® model, however, a good match was achieved between observed and measured data. The predicted petroleum generation is combined with published diagenetic cement data from the Elgin and Franklin fields to produce a composite model for petroleum generation, diagenetic cement and bitumen formation.

Abstract This chapter reviews and synthesizes the lithostratigraphy, biostratigraphy, chronostratigra-phy, and breccia types of the southwestern part of the great American carbonate bank in the southern Franklin Mountains (SFM), ElPaso, Texas. Primary stratigraphic units of focus are the Lower Ordovician El Paso and Upper Ordovician Montoya Groups. These groups preserve breccias formedbycollapse ofapaleocave system. Precambrianand Silurian units are discussed in the context of breccia clast composition and relative timing of breccia emplacement. Specific attention is paid to the juxtaposition of the top-Sauk second-order supersequence unconformity between the El Paso and Montoya Groups and its relationship to breccias above and below it. The unconformity represents a 10-m.y. exposure event that separates Upper and Lower Ordovician carbonates. The top-Sauk exposure has been previously documented as a significant karst horizon across much of North America. The breccias of the SFM were previously described as the result of collapsed paleocaves that formed during subaerial exposure related to the Sauk-Tippecanoe unconformity. A new approach in this work uses traditional field mapping combined with high-resolution (<1-m [<3.3-ft] point spacing) airborne light detection and ranging (LIDAR) data over 24 km 2 (9 mi 2 ) to map breccia and relevant stratal surfaces. Airborne LIDAR data were used to create a digital outcrop model of the SFM from which a detailed (1:2000 scale) geologic map was created. The geologic map includes formation, fault, and breccia contacts. The digital outcrop model was used to interpret three-dimensional spatial relationships of breccia bodies with respect to the current understanding of the tectonic and stratigraphic evolution of the SFM. The data presented here are used to discuss potential stratigraphic, temporal, and tectonic controls on the formation of caves within the study area that eventually collapsed to form the breccias currently exposed in outcrop.

First as a colonial American, and later as a patriot of outstanding importance, Benjamin Franklin (1706–1790) maintained a now little-known interest in geological questions. He began as a follower of the English theorists Burnet, Woodward, and Whiston but soon assimilated some of their ideas with original observations and speculations. Though long attentive to earthquakes and their possible causes, Franklin learned from interactions with other naturalists to broaden the range of his theorizing. Eventually, his earth science topics included the origin of springs and rivers, the Flood and the Abyss, natural convulsions of great power, strata and their distortions, the age of Earth, the nature of its core, the origin of mountains, the history of life, and the problem of extinction. Through his championing of American phenomena and thought, he not only contributed to the work of European savants but significantly enhanced our national presence and its prestige. Yet, if remembered in the history of American geology at all, Franklin has received far less attention than his accomplishments and influence deserve. Even those who purport to write on him and science too often neglect his theorizing about Earth. Though Franklin is appropriately remembered as a physicist, inventor, diplomat, author, and printer, we have apparently forgotten that, for more than sixty years, he maintained an active interest in the physical geography, dynamics, and history of our planet. America’s longtime intellectual leader in those fields as in others, Franklin was regarded worldwide as a significant geological philosopher.