Evolution of Middle Eocene Tide-Dominated Deltaic Sandstones, Lagunillas Field, Maracaibo Basin, Western Venezuela
Jesus Maguregui, Noel Tyler, 1991. "Evolution of Middle Eocene Tide-Dominated Deltaic Sandstones, Lagunillas Field, Maracaibo Basin, Western Venezuela", The Three-Dimensional Facies Architecture of Terrigenous Clastic Sediments and its Implications for Hydrocarbon Discovery and Recovery, Andrew D. Miall, Noel Tyler
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Interpretations of net-sand/percent-sand maps, well-log cross sections, vertical log-pattem trends, core descriptions, and log facies suggest that several aggradational tide-dominated deltaic cycles were deposited in Lagunillas field. Western Venezuela, during a widespread transgressive event at the end of the Middle Eocene. Reservoir lithofacies present are estuarine distributary-channel sandstones, tidal sand-ridge sandstones, prodelta/shelf assemblages, and tidal-channel facies. Geometries of the sandstone bodies are highly dip elongate and strike lenticular. These shoestring sands maintain their widths in a landward direction (west) and splay outward at their seaward limit (east), where loci of sand deposition occurred. Eastward, the sequence thickens concomitant with a decrease in sand-to-shale ratio. Individual correlatable depositional units are interpreted to be discrete delta lobes established during progradation of estuarine distributary systems. These single delta lobes shifted laterally along strike during infilling of deltaic depositional axes. Laterally persistent low-resistivity shale markers stratigraphically bound several delta lobes, which together constitute one of five deltaic cycles present in the upper reservoirs of the field.
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The Three-Dimensional Facies Architecture of Terrigenous Clastic Sediments and its Implications for Hydrocarbon Discovery and Recovery
While there has been much interest in recent years in concepts of sequence stratigraphy, this book focuses on stratigraphic units that are, in general, an order of magnitude smaller than sequences. A knowledge of such architectural detail is of considerable significance in the development of detailed, scaled facies models for depositional environments, and is of paramount importance in the efficient design of advanced petroleum recovery projects. This book is the outcome of a SEPM Research Symposium held at the annual meeting of the Society in San Antonio, Texas, April 1989. The intent of the meeting was to bring together modern research on facies architecture, and to apply this research to the investigation of reservoir heterogeneities and production problems.