|
1 Mobil North Sea Ltd, 3 Clements Inn, London, WC2A 2EB, UK
2 Core Magnetics, Sedbergh, Cumbria, LA10 5JS, UK
3 Department of Oceanography, University of Southampton, SO9 5NH, UK
Since the foundation of the science of geology, the description and comparison of preserved organic remains has been the fundamental means to determine the relative ages of sedimentary rock sequences and for correlating these sequences in different areas. Significant problems have arisen in dating and correlating those stratigraphic sequences which are impoverished in, or barren of, fossil remains. As a result, when compared to the plethora of stratigraphic data available for Phanerozoic marine sequences, stratigraphic information available for terrestrial sequences is sparse indeed. It is no surprise, therefore, that major questions in stratigraphy still remain for such periods as the Lower Permian, uppermost Carboniferous and Triassic, which are dominated by non-marine formations.
These problems are exacerbated in correlating and dating barren sequences encountered in offshore exploration and appraisal drilling, as the geoscientist has available normally only drill cuttings and occasional core samples to augment log interpretation. With this sparse dataset, the geoscientist must often make technical judgements on the correlation and continuity of potential hydrocarbon reservoir sections in different wells which may affect exploration and field development decisions. Correlation of biostratigraphically impoverished sequences therefore can be of great significance, as Permian, Triassic and uppermost Carboniferous hydrocarbon reservoirs are economically extremely important, with about 11 000 million barrels of oil equivalent being thus far discovered in these sequences on the UK Continental Shelf alone.
Improvements in analytical techniques during the past few decades have led to the development of geological subdisciplines, some of which, in turn, have potential in providing alternative
...
This 250-word extract was created in the absence of an abstract.
