Research on the interpretation method and its application of interference well test analysis for CBM drainage wells

Interference well test is an important method to determine the relation and connectivity and find the forma- tion characteristics between two wells. In interference well testing in CBM well under closed situation,the bottom pres- sure of the well is the superposition of recovery stress and composite pressure of the perturbed well after the disturb- ance,however,the background pressure of conventional interference well is uniform initial reservoir pressure or charac- terized by linear change. The paper presents a numerical multiple well test analysis method of net interference stress separation for the bottom pressure of CBM well and a mutual authentication method of interference well test interpreta- tion,such as numerical well test,the analysis of extreme value point and template fitting. Taking the analysis of A-B well group in the south of Qinshui Basin as an example,the connectivity between the two wells and the direction of permeability are the same as regional geological characteristics. The testing results play an important role in the fractu- ring design,and the development program in this area.