Abstract:Hydrocarbons have been produced from the Carboniferous of the East Midlands since the 1920s. Some 30 discoveries have been made to date and although field sizes are generally small, the relatively low costs have made exploration and development an attractive commercial proposition. Many of the factors which contribute to success in the East Midlands occur in other basins in Northern England but have not produced significant hydrocarbon accumulations. This paper examines the key attributes of the intra-Carboniferous play and through an integrated regional geological framework contrasts the successful East Midlands oil province with the other Carboniferous basins of Northern England.
In 1963, a specimen of a small, armoured reptile was discovered in the Red Beds formation in the Qacha's Nek Province of Lesotho, southern Africa. Unfortunately, the matrix in which the specimen is embedded is particularly hard and resistant to chemical action. Preparation must therefore be by mechanical means and is not yet complete. However, certain features of the osteology of the skull and postcranial skeleton of the specimen are clear and are described below. In both skull and postcranial material, features indicating that this is a relatively advanced crocodilian form are present. It will be shown that on the basis of these characters, this form must be included within the order Crocodilia. It is proposed to name this specimen Ortho‐suchus stormbergi. The discovery of a specimen possessing many diagnostic crocodilian characteristics in Upper Triassic beds is remarkable since hitherto it has been considered that these forms did not appear before the Jurassic. Indeed, our knowledge of Jurassic crocodiles is mainly limited to the more aquatic members owing to the dearth of continental deposits.
The Eakring Dukeswood oil field of Nottinghamshire was last produced in 1971. All wells have since been abandoned and the licence ML 1 expired on 22 April 1992. Cumulative production was small by North Sea standards, but during the Battle of the Atlantic the field produced the bulk of the UK's indigenous crude, peaking at 1600 BOPD in 1941. Cumulative recovery was some 6.5 MMSTB from an estimated 25.6 MMSTB in place in the completed horizons. In 1986 a study was undertaken to evaluate the remaining reserve potential.The primary tool for such work would normally be a detailed geological model, but since less than 25% of the 197 grid drilled wells have any wireline logs or cores only structural models existed. There is very little seismic. A further complication is that there were nine productive horizons and the majority of well completions were unsegregated over four of them. Only 20% of cumulative production can be assigned unequivocally to any one reservoir.Reservoir models, and individual reservoir contributions to production, had to be determined using less conventional techniques. Individual well performance under recycled peripheral water flood has proved to be a powerful tool to determine reservoir connectivity. Mapping decline rate reversal and water breakthrough by month indicates the transmissibility fairways and no-flow barriers in the system. It has also proved in some circumstances a useful discriminator of reservoir contribution.The reservoirs are mainly Westphalian A to Namurian B siliciclastics. All were undersaturated at initial conditions. Porosity is often secondary, rarely above 20% and absolute permeability ranges from less than 1 to several hundred mD. Irreducible water saturation (S wi ) from mercury injection data ranges between 30 and 50%o and water flood experiments indicated residual oil saturation (S or ) at 30%>. The oil is waxy, up to 16%) by weight, and has a high viscosity with correspondingly unfavourable mobility. API gravities range from 31.9-37.6°. Most production was obtained from the Loxley Edge Rock, the Sub Alton and Crawshaw sandstones-all by depletion drive, and from the Ashover Grit-in part water driven. Post-war water flooding was directed mainly at the Sub Alton and Crawshaw units.Regional studies and sedimentological examination of two recent adjacent wells established the likely broad reservoir anatomy. This was then refined for the field from the qualitative transmissibility maps constructed from flood front behaviour. Geological models could then be assembled with some confidence and bypassed oil and secondary accumulations were identified. Relative permeability experiments on the modern core indicate an additional field reservoir/accumulation, previously unrecognized.The Eakring Dukeswood oil field of Nottinghamshire ( Fig. 1) was developed during the 1939-1945 war. It provided much of the UK's indigenous crude oil at that time, and was last produced in 1971. Modern reservoir data acquisition was then in its infancy, and less than 25% of the wells have any petroph...
The southern boundary of the Nagssugtoqidian mobile belt was first mapped by Noe-Nygaard & Ramberg (1961) on the basis of the progressive deformation of a swarm of basic dykes - the Kangarniut dyke swarm. Field work in 1969 showed this boundary to have an approximate NE-SW strike (Eseher et al., 1970). The object of the summer's field work reported on here was to continue the investigations along the Nagssugtoqidian boundary and to study the deformation- metamorphism-dyking relationships in the western part between Holsteinsborg and Kangamiut. The field work formed part of a joint project involving the University of Liverpool. Transport in the field was supplied by the GGU cutter "A. Kornerup" with Orla Norsk as skipper.
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