Abstract:

Middle Jurassic Series in Turpan Depression could be divided into four facies such as river,delta,fan-delta and lake facies.The Xishanyao Formation is meandering river facies,the Sanjianfang Formation is delta facies,the Sanjianfang-Qiketai Formations contain delta and lacustrine facies deposits.The river channel sandbodies in the Xishanyao Formation and the subaqueous distributary channel sandbodies in the delta front of Sanjianfang Formation contain mainly secondary solution pores,and have high porosity and high permeability.The subaqueous distributary channel sandbodies in the fan-delta front of Sanjianfang-Qiketai Formations contain poor secondary pores,they are denes and poor reservoir bodies with low porosity and permeability.The loss of primary porosity is caused by compaction,and pore texture reformation is resulted from the solution of unstable components.