Sedimentary characteristics and evolution mechanism of Ordovician pre-salt dolomite reservoirs in the central and eastern Ordos Basin
The carbonate-evaporite system of the Majiagou Formation under salt beds in the Ordos Basin is an important strata for future oil and gas exploration.The special pattern of carbonate-evaporite will cause subsequent differential dissolution and filling of diagenetic fluids,further increasing the complexity of pre-salt carbonate reservoirs and making it more difficult to predict the distribution of high-quality reservoirs.Therefore,this study took the pre-salt of the Majiagou Formation in the Ordos Basin as the research object,and conducted reservoir geology research based on cores,thin sections,physical property data,etc.,and identified 15 rock types and 10 types of facies association.It clarifies that pre-salt reservoir types include gypsum-pore dolomite reservoirs,grained dolomite reservoirs,leopard dolomite reservoirs,crystal dolomite reservoirs and microbial dolomite reservoirs.Based on the analysis of pore origin and evolution,the geological model of dolomite reservoir under salt beds development is established,which is"favorable sedimentary facies+pore formation in the early diagenetic stage+stable preservation of pores in carbonate-evaporite systems".The research results can deepen the understanding of the origin and preservation mechanism of pores in carbonate reservoir under salt beds,and have important practical significance for the development of oil and gas resources in the Ordos Basin.
Carbonate reservoir under salt bedsOrdos BasinReservoir originMajiagou Formation
万方数据
维普
