Sequence stratigraphic interpretation of Cretaceous through Miocene, Barcoo sub-basin, Browse Basin, Northwest Shelf of Australia.

摘要

The petroleum exploration in Australia started in the nineteenth century. However, due to little exploration activity only one well has been drilled for every 1300 km2 of sedimentary basins. In fact Australia (apart from Antarctica) is the least explored continent on earth (Longley, 2001).;The Northwest Shelf of Australia is composed of Mesozoic intracratonic basins, including four major basins: the (Northern) Carnarvon, offshore Canning, Browse and Bonaparte Basins. Browse Basin is the significant essential unexplored petroleum-bearing sedimentary basin of the Northwest Shelf. The study area is located in the Barcoo Sub-basin, which is a major depocenter of the Browse Basin. During the Cretaceous through Miocene Ages, sediments of the Barcoo sub-basin were deposited and thicken seaward to the northwest.;The main purpose of this study is to analyze the sequence stratigraphic framework of Cretaceous through middle Miocene strata. The analysis of 2D seismic and well log data allows constructing a depositional and chronostratigraphic framework of the study area. The data were integrated to identify and correlate 7 major sequence boundaries or major surfaces. Each sequence was subdivided into separate seismic descriptions characterized by specific internal reflection configuration, reflection amplitude and reflection continuity. Six depositional sequences were recognized (145.5-112.0, 112.0-89.3, 89.3-65.5, 65.5-23.0, 23.0-19.0 and 19.0-14.2 Ma) and summarized in detail with structural, isochron, seismic facies, and geologic facies maps.;Potential reservoir sands can be found in delta fronts, lower shorefaces, upper shorefaces, foreshores and mouth bars as well as in basin-floor fans, and prograding wedges. However, no field has been discovered or developed within the study area. The failures of the exploration wells are due to the relationship between hydrocarbon generations and timing of source rock in relation to the formation of the structures.;The future study of the deep targeted seismic, stratigraphic plays, and basin analysis is recommended. The exploration activity is necessary to make the Northwest Shelf to be a major petroleum province of the world in the future.