OIL RESERVOIR TYPES AND THEIR CONTROLLING FACTORS IN LINGYANDING REGION, THE NORTHWEST ORDOS BASIN

In this paper,the oil reservoirs in the Middle-Lower Jurassic Yan'an Formation and the Upper Triassic Yanchang Formation of Lingyanding region,the Northwest Ordos Basin are classified into five types,that is,the tectonic-lithologic composite oil reservoir,the top-changing screened oil reservoir,the strata overlapping oil reservoir,etc.The characters of various oil reservoirs of different types are expounded.It is pointed out that the oil resservoirs in the study area are dominated by the composite type.Combined with tectonic location where each type of oil reservoir situated as well as paleogeomorphic forms and lithofacies features,the influences and controlling action of different sedimentary facies and different types of tectonics on the formation of oil reservoirs are also discussed.