Seismic Imaging of a Cretaceous Fluvial System

Claudia Velez
University of Delaware Geological Sciences Newark, Delaware
[email protected]

The Potomac Formation, which was deposited in an aggrading coastal plain during the Early Cretaceous, is a potential production-scale ancient analog for fluvial reservoirs in a passive margin, alluvial plain setting. In northern Delaware, these sediments onlap Paleozoic metamorphic basement, are truncated by an unconformity, and are found at depths of 10 – 300 m, which makes this formation ideal for the geologic characterization of fluvial deposits through seismic and drilling methods. A 35-km high-resolution seismic reflection dataset will be collected and integrated with sequence stratigraphic analysis, samples from two cores that will be drilled during the project, and geophysical log datasets in order to better characterize the facies, porosity, and permeability distribution of these deposits, and to test the current sequence stratigraphic model for this Formationin, in which lowstand periods are characterized by sand-prone intervals whereas transgressive and highstand periods are characterized by more mud-prone intervals. This project will make a contribution to better understanding how the sequence stratigraphic framework, geometry, and permeability distribution of the deposits of an ancient fluvial analog in a passive margin affect the distribution of fluid flow pathways and barriers. The findings should lead to a better characterization of the stratigraphic architecture of alluvial facies of the Potomac Formation, and to improve understanding of the geometry and heterogeneity of fluvial reservoirs in similar passive margin alluvial plain sequences, which in turn provides information helpful to devising production strategies that allow the maximization of oil and gas recovery in similar deposits.

AAPG Search and Discovery Article #90070 © 2007 AAPG Foundation Grants in Aid