Problems and Methods for Optimization of Hydraulic Fracturing of Deep Coal Beds in China

Abstract

Geological coalbed methane (CBM ) reserves buried at a depth of about 2000 m in China amount ar e estimated at 36.81 trillion m 3 , ranking China as third in the world. Resources buried at depths greater than 1000 m account for 61.2% of total reserves. Compared with currently developed shallow coal seams, the deep beds have much more complex mechanical engineering characteristics: high in situ stress, high temperature, high karst water pressure, considerable mining disturbance, etc. Therefore hydraulic fracturing operations for deep coalbed methane (DCBM) are associated with problems that are not typical for shallow beds. Accordingly, in order to develop deep bed fracturing technology, we need to study types of proppants, fracturing fluids, fracturing supporting technology, etc. based on results of hydraulic fracturing of shallow coal seams.