Abstract:
In this study,the samples were taken from the wells of Qinshui Basin with depth more than 800 meters. Geo- logical features of deep coal seam were summarized. The fracturing difficulties were also analyzed. According to the sta- tistics of fracturing data from 10 deep wells,which used active water fracturing technologies and obtained some good effects,the characteristics of fracturing construction parameters for deep CBM wells using the existing technologies were summarized. The factors that cause the abnormal high pressure of fracturing in deep coal bed gas reservoir were analyzed. The strategies of deep coalbed methane reservoir were proposed. The research results show that deep coal beds have high temperature,high pressure,high ground stress,poor reservoir physical properties and strong heterogene- ity,which makes the applicability and validity of the existing technologies face severe challenges. The vertical well fracturing uses large volume injection and 15% sand ratio. Abnormal pressure of fracturing is influenced by fracturing fluid properties,the formation of micro fractures,reservoir lithology,drilling fluid pollution,coal blockage and other factors. The development of deep coal beds in the future depends on not only the optimization of active water fracturing technology,but also the promotion of fracturing theories and the development of new materials.