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ABSTRACT: The Georges Bank Basin: A Quantitative Basin Analysis Study

J. Liu, Ian Lerche, A. Bissada, J. Lacey

Using a one-dimensional fluid-flow/compaction model applied to well data of the Georges Bank Basin, East Coast, United States, has enabled a simulation to be made of the history of the sedimentation, basement subsidence, tectonic activity, paleoheat flux evolution, maturation of organic matter, hydrocarbon generation, and migration tendency.

Five major aspects are addressed.

(1) The use of the model and well data to review the histories of basement subsidence, sediment fill, compaction and diagenetic processes, as well as to examine the relations between the basin's geohistory and

geotectonic setting. Five stages have been recognized and correlated with the evolution process of the East Coast continental margin.

(2) The application of an inversion method to vitrinite reflectance (VR) values measured at different depths of the well to reconstruct the heat-flux history, paleotemperature variations, and the maturation history of organic matter. The influences of fluid content, fluid composition, salt diapir, and igneous intrusives on the heat flux have also been simulated and are discussed.

(3) The application of an end-member analysis method to the VR distributions at each depth to examine the trustworthiness of the VR inversion results, and also to determine the relation between mixing proportions of vitrinite end-members in the stratigraphic sequence in relation to petrographic or sedimentary environmental conditions. The results show that the VR distribution spectra can be used as geological environment indicators.

(4) The use of a hydrocarbon generation model to give a prediction for hydrocarbon generation timing, and for cumulative hydrocarbon amounts in different time periods and different formations of the basin.

(5) The simulation of excess fluid pressure in the strata to estimate the probable tendency of hydrocarbon generation and migration, and to simulate reservoir quality so that an assessment of potential hydrocarbon traps can be made.

AAPG Search and Discovery Article #91003©1990 AAPG Annual Convention, San Francisco, California, June 3-6, 1990