SHALLOW-MARINE MICROPOROUS CARBONATE RESERVOIR ROCKS IN THE MIDDLE EAST: RELATIONSHIP WITH SEAWATER Mg/Ca RATIO AND EUSTATIC SEA LEVEL
1 University of Geneva, Earth and Environmental Sciences, Department of Geology and Paleontology, Rue des Maraîchers 13, 1205 Genève, Switzerland.
2 K.U. Leuven, Department
of Earth and Environmental Sciences, Celestijnenlaan 200E, 3001
3 Total Exploration and Production, CSTJF,
Avenue Laribau, 64000
* Corresponding author, email: Chadia.Volery@unige.ch & firstname.lastname@example.org
The formation of shallow-marine microporous carbonate reservoir rocks remains
poorly understood in spite of their economic importance, particularly in the
An inventory of carbonate formations in the Middle East was compiled for three geological time intervals characterised by different seawater chemistries: the Late Carboniferous to Triassic (aragonite seas); the Cretaceous (calcite seas); and the Cenozoic (transitional from calcite to aragonite seas). For each time interval, carbonate formations described as microporous have been listed.
During the Cretaceous calcite sea, eleven microporous carbonate
formations were deposited in the
The relatively high stability of low-Mg calcite muds may explain why shallow-marine microporous carbonates formed during time intervals with calcite seas. In contrast to muds composed of aragonite or high-Mg calcite crystals, the original microfabric (including intercrystalline microporosity) of low-Mg calcite muds can partly survive moderate diagenesis.
Key words: Microporosity, micrite, carbonates,
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