William E. Galloway1
(1) University of Texas at Austin, Austin, TX
ABSTRACT: Evolution of the Depositional Systems and Genetic Stratigraphic Paradigms-How We Predict, Project, and Characterize Sandstone Reservoirs
In the 1950's the idea that an understanding how sand was deposited could be applied to the practical business of finding and producing hydrocarbons stirred the imaginations of a relatively small group of geologists working primarily within the nascent research groups of several petroleum companies. A half century of applied sedimentology ensued. The consequent depositional systems paradigm emphasized physical process of deposition, attributes of resultant deposits, and the geometry and spatial relationships among 3-D sediment bodies. Like most geological concepts, genetic stratigraphy began with simplistic models and evolved into an elaborate interpretation framework. Systems analysis was, to a degree, diverted from its environment/process/facies orientation with the popularization of sequence stratigraphy. However, as sequence studies increasingly stressed the integration of surfaces with understanding of the physical processes that form them and with the diversity of facies that surround them, a regeneration has occurred.
Studies of the Rhone delta and continental margin provide a microcosm of the evolution of depositional systems analysis. First papers developed the process and facies framework model of wave-dominated deltas. A second cluster of papers looked to the Rhone shelf for analogs of low-stand deposits of then-popular sequence models. Recent papers have emphasized the relationship of the Quaternary Rhone to the larger sediment transport system that creates sediment bodies and surfaces found along strike and beyond the shelf edge. Increasingly, facies and surfaces have been integrated into a coherent 3-D picture, still incomplete, of the interrelated family of reservoir sand bodies produced in and around a sandy, wave-dominated delta system during a regime cycle.
AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado