Comprehensive quantitative evaluation method of sealing oil-gas ability of caprock and its application

A comprehensive quantitative evaluation method of sealing oil-gas ability of caprock was established based on the study of sealing oil-gas of caprock and its influence factors in order to exactly evaluate sealing oil-gas ability of caprock. The concept of space distribution continuity of caprock and sealing ability efficiency of caprock and the weighting average method were used. The method was applied in evaluating comprehensively and quantitatively sealing gas ability of caprock of 14 volcanic gas reservoirs of Yingcheng formation in Xujiaweizi depression. Results indicate that the sealing gas ability of caprock of 10 volcanic gas reservoirs of Yingcheng formation in Xujiaweizi depression is stronger and the strongest, except the sealing gas ability of caprock of 4 volcanic gas reservoir is middle, which is favorable for gas to accumulate and preserve.