Oil-gas Resource Assessment Of Wuerxun Depression Of The Hailar Basin

Halar Basin Wuerxun depression is located in Hulunbeir of Inner Mongolia Autonomous Region, with Mongolia Zagat Basin Tarim Basin unity, which is in Northeast Asia as part of the Late Mesozoic rift system.The source rocks of Damoguaihe, Nantun Tongbomiao Formation lay a good foundation for oil and gas resources of Wuerxun Depression . There is a big difficulty in the exploration of Wuerxun depression, evaluation of the depression, there are many predecessors, but found the specific sources of oil and gas still in doubt because of its complexity and difficulties exist: Hailar Basin is a typical rift basin, with multi-source, short source, phase change fast, and complex fault system characteristics.To solve this problem, the article is based on the lastest stratification, through improved source rock evaluation criteria, identified the main source layer of Wuerxun depression ,and apply chemical kinetics method, the main element for oil and gas source rock formation for the resource assessment, combining with the corresponding accumulation factor, calculating the total oil and gas resources. The results show that the erosion of Wuerxun depression is mainly between 68-99.6Ma, the other for the normal deposition. The geothermal gradient is low from the period of Tongbomiao , to a significant increase during the period of the second member of Nantun Formation , since the Qingyuangang period beginning to decline, the present geothermal gradient is too low to generate hydrocarbon. The main hydrocarbon generation time of Wuerxun depression is between the 130-90Ma. The total quantity of oil generation in Wuerxun depression is 2.066 billion tons, the total gas volume of Wuerxun depression is 6.82 billion cubic meters, with a total resource of 317 million tons of oil.The first member of Nantun Formation and the special lithologic Formation produce a large amount of oil.depression accounted for 30% and 21.35% of the total quantity of oil generation.