Analysis and Diagnosis of CBM Fractured Wells’ Productivity Damage in the Middle of Qinshui Basin, China

CBM differs from conventional reservoirs, which is easily damaged with complex factors. There were massive papers on CBM damage mechanism, but with fewer studies on pollution types and stimulating measures. This paper studies various factors on SHI Zhuang CBM field’s production from the perspective of geology, engineering and drainage, establishes typical production model to determine reservoir pollution types, and builds up well and layer selection standard for recovering potential reservoirs. The result proves that impacts on CBM wells productivity cannot be ignored because their damages are huge, such as subsided column, fracturing fluid soaking time, fracturing problems, pumping efficiency, drainage time interval, production efficiency, and liquid loading rates etc. Major factors’ determination and typical curves’ establishment offer references on reservoir diagnosis, which is of great significance on layer selecting stimulation of inefficient wells.