Geological Controls on Pore Geometry of Upper Kharaib Reservoir, Offshore Abu Dhabi, U.A.E.
Jun-Ichi Saotome, Toshiaki Shibasaki, Tsuyoshi Shikama, Ken-Ichi Kawaguchi, 2000. "Geological Controls on Pore Geometry of Upper Kharaib Reservoir, Offshore Abu Dhabi, U.A.E.", Middle East Models of Jurassic/Cretaceous Carbonate Systems, Abdulrahman S. Alsharhan, Robert W. Scott
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The upper Kharaib reservoir of the Lower Cretaceous Thamama Group is one of the major oil-producing horizons offshore Abu Dhabi in the United Arab Emirates, and is traced over the area as a well-defined rock unit. This reservoir is composed of three lithofacies, rudistid-peloidal grainstone/packstone, algal-peloidal grainstone/packstone, and bioclastic wackestone/mudstone. Sediments were deposited on a broad carbonate shelf and show an upward-shallowing succession. Reservoir quality is determined by both original depositional fabric and subsequent diagenetic processes. In general, permeability is variable and porosity is constant throughout the sequence, except for stylolitized intervals.
In the “A” field, six high-permeability facies are identified in the grain-supported interval. These facies are characterized by unique pore-throat size distributions resulting from depositional textures and diagenetic modification. Grain sorting and preferential dissolution, as well as preservation of primary pores, are significant factors in controlling pore geometry. Dolomitization is also locally important. The highest permeability is present in well-sorted, coarse-sized grainstone at the basal part of upward-fining bed sets where well connected intergranular pores are preserved.
Thus, identification of high-permeability facies is crucial if one is to understand the performance of the reservoir under water flood. On the basis of the vertical and lateral distribution of high-permeability facies and pore-throat size distribution, the reservoir was divided into twenty-two sublayers as a basis for reservoir simulation study.
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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.