Print this pageDo High Resolution Sequence Stratigraphic Studies of Quaternary Strata Yield Useful Results for Oil and Gas Exploration?
ANDERSON, JOHN B., LAURA A. BANFIELD, PHILIP J. BART, BRENDA J. ECKLES, ANTONIO B. RODRIGUEZ, JENNIFER N. SNOW
A long term study of the northern Gulf of Mexico continental shelf and upper slope focuses on examining the response of different depositional systems (fluvial, deltaic, coastal, etc.) to rising and falling sea level during the last few glacial eustatic cycles. The data base consists of over 20,000 kilometers of high resolution seismic data and several hundred oil company platform borings and cores. The study area extends from the west Florida shelf to the Rio Grande and includes very different fluvial input, shelf gradient, and climatic and oceanographic shelf settings.
A series of strike and dip-oriented cross sections and paleogeographic maps extending across the study area and coinciding with prominent seismic stratigraphic surfaces illustrate how deposition varied from one area to the next at specific times and sea-level positions. These surfaces include the maximum flooding surface of the last highstand, the sequence boundary associated with the subsequent lowstand and the following transgressive ravinement surface. Variations between deposits are profound. In some areas the stratigraphic section is dominated by highstand deposits while other areas are dominated by transgressive and/or lowstand deposits. Potential time equivalent reservoirs also vary along the shelf. For example, highstand sand bodies are dominantly deltaic deposits on the south Texas and west Florida shelves and barrier/bar sands on the central Texas shelf. Reasonable repetition of depositional systems occurs within any given area over several glacial eustatic cycles. Therefore, predictable trends are observed in terms of reservoir character, shape, and stratigraphic position.