Outcrop, Subsurface, and Seismic Mapping of a Basal Transgressive Sand: ABSTRACT

Basal transgressive sands can be defined by a careful integration of outcrop, well, and seismic data within the concept of an unconformity-bounded depositional sequence. This integration permits accurate prediction of potential stratigraphic traps. Only moderate attention has been paid to the basal transgressive sand as a prime objective reservoir for oil and gas accumulation. In the past it has generally not been recognized as a separate genetic unit, but grouped with the underlying deltaic and/or fluvial sand. The basal transgressive sand can be easily distinguished commonly only over areas of igneous, metamorphic, and folded sedimentary terrains. Through analysis of the lithologic, biologic, acoustic, and bore-hole characteristics of the basal transgressive sand, poten ial hydrocarbon trap geometries can be identified. This approach has been applied in an analysis of geologic and geophysical data from the United States, Argentina, and Australia. End_of_Article - Last_Page 233------------