Influence of medium and high coal rank on coalbed methane recovery ratio

To reveal the effect of coal rank on recovery ratio during the coalbed methane exploitation process, this paper analyzed the relationship between coal rank and recovery ratio, and revealed that there are some regularity changes among coal rank and porosity, gas storage properties, desorption rates in medium and high rank coal reservoirs. This study was based the theory of the origin and occurrence of coalbed methane, the previous studies, and combining with the actual drilling data of Qinshui basin coalbed methane wells. The results show that, the medium and high coal rank on recovery ratio is mainly affected by porosity, gas storage properties and desorption rates. The greater the value of porosity, gas storage properties and desorption rates, the higher the recovery ratio. The conclusion of this study has shed some light on the productivity and workability analysis.