Research On Oil-gas Content Characteristics Of Ordovician Buried-hill In Lunnan Area In Tarim Basin

Great burial-depth, low porosity ,and strong heterogeneity are the basic characteristics of the Ordovician carbonate reservoir in Lunnan area of Tarim basin. Because seismic resolution is limited, it is difficult to forecast reservoir in laterally. Exploration of oil and gas of Ordovician is limited by unclear acknowledge about distribution of oil and gas and thin-research about geologic base.According to research of this paper, find that the oil of normal gravity is mainly derived from the source rock of Middle-Upper Ordovician, natural gas from Cambrian source rock with high temperature cracking.Applying fractual dimension theory, research fracture of Ordovician and find the correspondence relation of fault-condensed belt and fracture of reservoir in plane, and point out the development area of fractural reservoir. Applying well data, karst system is grouped in vertical direction. And its characteristics of surface-direction are found. And find that the solution cavity and fracture are the principal space of storage and seepage of oil and gas. The principal controlling factor of reservoir property is analyzed. Formation deposit term is researched. And point out that normal of specific gravity oil and natural gas are production of different source rock and different formation term. And explain the heary-visous oil of the Tahe field. Distribution law of oil and gas of Lunnan area is summarized. Point out that distribution of the gas of Ordovician relates with large-fault only. And think pinching belt of mid-up Ordovician is exploration area of oil and gas in future.