Volcanic-rock Facies and Reservoir Characteristics in the Northwest of Junggar Basin

A number of volcanic-rock reservoirs were found in the Carboniferous-Permian system in the northwestern margin of Junggar Basin,they were one of the targets and assignable strata for oilfield exploration and development.By using a large number of data of core analysis,dynamic development data,well drilling,well logging and oil test data,the volcanic-rock facies and reservoir characteristics were studied.The results show that the volcanic activity is strictly controlled by faults in the northwest of Junggar Basin,volcanic rocks are distributed along the both sides of the faults and the lithology of volcanic rocks is controlled by the modes of volcanic eruption and volcanic facies.The formation of volcanic-rock reservoir has experienced a long-term evolution.Influenced by structure,weathering and erosion,the complex reservoirs with pores and cracks of the various causes of reservoir space are formed.