Geology characteristics and exploration strategy of Mesozoic large and medium oilfields in Southern Ordos Basin

In order to find out the Mesozoic oil-gas distribution regulation,design a practical and effectual strategy of exploration disposition,and realize an oil-gas breakthrough and oilfield discovery as soon as possible in the southern Ordos Basin,the petroleum geologic conditions of the basin were systematically analyzed and exploration and development practices were wholly examined.It shows that the Mesozoic oil and gas in the basin are generated,distributed,gathered and accumulated in large scales,and the gathering degrees of oil-gas in different layers and spaces are different,presenting a complicated and variable complexion.The main oil pool types are of subtle structural-lithologic oil pools and lithologic oil pools.A large size advantageous sedimentary facies belt and a low partial vertical relief structure,and large-scale and low vertical relief structure setting formed by a series of partial low vertical relief structure are the main factors of controlling the large scale oil pool formation,and are also the basic condition of forming large-medium-sized oilfields.Conclusion: Mesozoic Southern Ordos Basin has the geology condition of growing large-medium-sized oilfields,but the exploration means is restricted by the condition of geography and surface feature.A scale exploration strategy should be performed,taking into account both upper and lower oil layers and taking drilling as the main means.