HYDROCARBON ACCUMULATION AND EXPLORATION POTENTIAL OF PALEOZOIC CARBONATE IN THE UNITED ARAB EMIRATES

The Palaeozoic is the major gas producing strata of the Persian Gulf Basin. The gas of Paleozoic in the United Arab Emirates (UAE) is accumulated in the carbonate reservoir of Khuff Formation of the Upper Permian. In this paper, the main controlling factors of carbonate reservoir over petroleum accumulation are analyzed on the basis of tectonic and sedimentary evolution. Two types of favorable exploration zone are optimized, and the exploration direction of Palaeozoic in this region is indicated. The results show that the Paleozoic in the UAE can be subdivided into four tectonic evolutionary stages. Tectonic evolution has important impacts on hydrocarbon accumulation, and the oil and gas found in the Paleozoic is mainly distributed in the deposits formed in the passive continental margin stage. The distribution and the size of hydrocarbon source kitchen of the Qusaiba hot shale are the factors which control the oil and gas distribution and scale of resources. The halite in the Khuff Formation is the main cap of Paleozoic reservoirs, and controls the vertical and spatial distribution of oil and gas. The rich zone of oil and gas is apparently controlled by the lithofacies distribution of the Khuff Formation, and hydrocarbon discoveries mainly occur in the carbonate shelf grain limestone -packstone facies belt. The surrounding basement high of the hot shale hydrocarbon generation kitchen is the favorable migration and accumulation area of oil and gas. The Khuff Formation of the United Arab Emirates still has large exploration potential. The overlapping areas of halite cap and high quality reservoir facies belt, and adjacent hot shale hydrocarbon generation kitchen, provide excellent conditions for hydrocarbon accumulation. The anticline structures and lithology-stratigraphic type of traps in this area are critical for oil and gas exploration in the Paleozoic.