Stylolites in Lower Cretaceous Carbonate Reservoirs, U.A.E.
Abdulrahman S. Alsharhan, James L. Sadd, 2000. "Stylolites in Lower Cretaceous Carbonate Reservoirs, U.A.E.", Middle East Models of Jurassic/Cretaceous Carbonate Systems, Abdulrahman S. Alsharhan, Robert W. Scott
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The major Lower Cretaceous reservoirs of the United Arab Emirates (U.A.E.) are characterized by stylolite-rich zones. Although their distribution and frequency are variable, stylolites tend to be most common and abundant toward the flanks of the fields. Three main types of stylolites are found in these reservoirs, each characterized by variations in amplitude, morphology, lateral continuity, and thickness of the accumulated insoluble residue. The recorded stylolites are classified as rectangular or high amplitude, solution seams or wave-like, and wispy seams or horsetail. The composition of the relatively insoluble seam material is variable, and depends mainly upon the composition of the nearby host rock. Most of the seams are composed of clay minerals, black bitumen, pyrite, and fine- to medium-grained calcite crystals or dolomite rhombs. Stylolites affect the petrophysical characteristics (porosity/permeability) and thickness reduction (compaction). The lower porosity and permeability values are found associated with the well-developed stylolites. Most stylolites observed in cores are parallel to subparallel to bedding (the horizontal type), indicating the predominance of vertical stress imposed by overburden pressure in stylolite formation. This also suggests a relative absence of tectonic or metamorphic activity in the area, which might produce inclined to vertical stylolites, although vertical to subvertical tension fractures are found associated with the well developed stylolites.
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Middle East Models of Jurassic/Cretaceous Carbonate Systems
This volume will interest tectonic modelers, stratigraphers, sedimentologists, and explorationists. It is the product of the international conference of “Jurassic/Cretaceous Carbonate Platform-Basin Systems, Middle East Models” that was convened in December 1997 jointly by SEPM (Society for Sedimentary Geology) and the United Arab Emirates University in Al Ain, United Arab Emirates. The twenty-three papers present new data and interpretations arranged in three sections: 1) sequence stratigraphy, cyclostratigraphy, chronostratigraphy, and tectonic influences, 2) depositional and diagenetic models of carbonate platforms, and 3) hydrocarbon habitat and exploration/development case studies. New tectonic models of the Arabian Basin, new stratigraphic and sequence stratigraphic reference sections, new geochemical and source rock data, and new reservoir data are presented. New geologic models make this set of papers relevant to geoscientists working outside of Arabia also.