C.A. WATKINS, B. RICH, N. BUTLER N.V. USTINOV, , V.A. BASOV AND L.A. FEFILOVA.
1Fugro Robertson Ltd., UK, 2VNIIOkeangeologia, Russia, 3Independent Consultant

In both Norwegian and Russian waters the Late Triassic to Early Middle Jurassic represents a key stratigraphic interval for reservoir development, but the disparate data sources and exploration histories have resulted in a relatively poor understanding of the similarity and differences between the two areas.

Of particular issue are the problems associated with the widespread use of lithostratigraphic nomenclature, that results in problematic correlation between Norway and Russia. As part of a recently completed review of the geology of the entire Barents Sea region (Fugro Robertson Ltd., in cooperation with the All Russia Research Institute for Mineral Resources of the World Ocean (VNIIOkeangeologia)), a new chronostratigraphic zonation scheme has been generated for all released wells in Norwegian waters and published data from selected key wells in the Russian Barents sea. The scheme is based on the analysis of well logs, core material and an extensive review of all available biostratigraphic data, and new biostratigraphic analyses by VNIIOkeangeologia.

Examples will be presented that justify the picking of the surfaces, which were defined by correlation of well sections using facies interpretation and sequence stratigraphic principles. There was no intention to rigorously apply any specific sequence stratigraphic methodology. Rather, the surfaces represent a series of candidate sequence boundaries and flooding events that are constrained by the available quantitative biostratigraphic events. The process was iterative, involving the testing of alternative possible correlations within the constraints provided by the available biostratigraphy.

The scheme provides a basis by which the genetically related packages between Norway and Russia can be assessed and forms the basis for a discussion of the nature of the Late Triassic to Early Jurassic interval in the region as a whole. A series of major, regionally extensive stratal surfaces are identified and areas of remaining uncertainty are highlighted. The implications for the regional stratigraphy and palaeogeography of the Late Triassic to earliest Jurassic interval are briefly discussed.