Rebuilding Paleogeomorphology of Pre-Jurassic and Oil-Gas Accumulation Regulation in Zhoujiawan Area

Pre-Jurassic paleogeomorphology controls not only the deposit and development of the Early Jurassic but also oilgas accumulation regulation. It is important to rebuild the paleogeomorphology accurately for oil-gas exploration of the Jurassic. Taking the Zhoujiawan area in the Ordos basin as an example and using 3D reservoir modeling techniques and an interpretation of the geology, drilling and logging, this paper rebuilds the paleogeomorphology of the pre-Jurassic based on analyses of sedimentary facies, sand body, flow direction, paleoburial depth reconstruction and paleobathymetric correction. At the same time, 3D sand body, porosity and permeability models are built. Using oil-gas reservoir forming conditions such as generating, storing, covering, trapping, migrating and preserving, the model visually interprets the regulations of oil-gas accumulation. According to the above models, favorable hydrocarbon accumulation areas are forecasted. They are located on the sand body of river marginal banks and the channel bars of river valleys on the three ramp reservoir regions. The models offer reliable evidence for exploratory development.