The case for enhanced coalbed methane using hydraulic fracturing in the geostructural belt

Coal and gas outbursts mostly occur during mining at geostructural belts. Pre-drainage coalbed methane using hydraulic fracturing is one of the methods to prevent outbursts. However, the coal in geostructural belts is to be soft and crushed with special mechanical properties and pore structure. To explore the feasibility of hydraulic fracturing in geostructural belts, a field investigation on enhanced coalbed methane using hydraulic fracturing with vertical well was conducted at the Yangquan Coalfield, China. This case puts forward a method for the location selection of vertical well in geostructural belts. In addition, a triple-control technology for hydraulic fracturing, which is characterized by pressure control, flow control and sand ratio control of fracturing fluid, is presented. The results show that the average gas production and maximum gas drainage capacity of the test well were 5.67 and 12.88 times than those of the regular well, respectively, achieving good drainage effects.