Sealing condition for high effective large and medium scale gas fields formation in rift basins in China

Through analysis on sealing characteristics of large and medium scale gas fields of rift basins in China,this paper defines and calculates comprehensive evaluation parameters of sealing capacity and gas accumulation efficiency for gas reservoir.Study on relation between gas accumulation efficiency and its sealing capacity comprehensive evaluation parameters of 16 large and medium scale gas fields of rift basins in China shows that,they have direct proportion relation,i.e.,the more the sealing capacity comprehensive evaluation parameter is,the higher the gas accumulation efficiency is,and vise versa.The minimum value of sealing capacity comprehensive evaluation parameter needed by high effective large and medium scale gas fields formation in rift basin is 0.2×10-4Pa2·s.