Characteristics and Controlling Factors of Cambrian Dolomite Reservoirs in the Northern Tarim Basin

Abstract

The discoveries of oil in YM32, the fluid oil and abundant secondary porosity in TS1 well provide the exploration of deep dolostone in Tarim basin with important references. The dolomites are characterized by old age, deep burial and complex diagenesis, thickly and extensively distributed in Cambrian stratum. The spaces of the Cambrian dolomite reservoir are composed of three groups: pores, fractures and combinations. And the dissolved pore and hole, the dissolved fracture and the combinations are absolutely in advantage. The paper discussed the main factors controlling the development of the dolomite reservoirs, and proved that the favorable sedimentary facies belts, various corrosions and hydrothermal activities are the key factors to form favorable dolomite reservoirs. Especially, the favorable sedimentary facies belts are the base of good dolomite reservoirs, the syngenetic karst and dolomitisation laid a solid foundation for secondary pore, and the hydrothermal corrosion is the key factor for well developed dolomite reservoirs.