The effectiveness assessment of gas accumulation processes in Kuqa depression,Tarim Basin,Northwest China

The effectiveness of gas accumulation processes is controlled by several main geological factors in-cluding charging force,features of gas conduit,sealing properties of caprock,etc. Based on the analysis and statistics of the large-medium size gas accumulations in China,the main parameters,in-cluding the excess pressure difference between the source rock and reservoir bed,the area coefficient of the gas conduit,and the thickness or displacement pressure of caprock,and the criteria for the as-sessment of gas accumulation processes have been established. Using the parameters and the criteria above,the effectiveness of gas accumulation processes in the Kuqa depression was quantitatively evaluated. By integrating the parameters of the excess pressure difference between the source rock and reservoir bed,the area coefficient of fault conduit system,and the caprock thickness in gas charging period,a comprehensive assessment of the effectiveness of gas accumulation in the Kuqa depression has been made. The result reveals that the Tubei-Dawan area,the Central Kelasu area and the Dongqiu-Dina area are three highly-effective areas for gas accumulation in the Kuqa depression.