| Coalbed methane (CBM) belongs to unconventional natural gas, which is both generated and stored in coal bed. In China, it is the most reliable alternative energy after coal, petroleum and natural gas. China’s coalbed methane resources are extremely rich, ranking third in the world. Because of strong tectonic movements, coalbed methane in China usually comes with low saturation, low permeability, low pressure, and severe heterogeneity.Hydraulic fracturing is the major way in improving recovery of CBM. In China, we also tried to increase the permeability of the coal reservoir by hydraulic fracturing. Due to the low permeability of the coal reservoir in China, plastic deformation occurred and fracturing fluid caused serious damage to coal seam permeability during hydraulic fracturing operation. Therefore hydraulic fracturing couldn’t achieve ideal effects in some coal seams in China, There is an urgent need to explore a set of stimulation and development techniques suitable for the characteristics of China’s coalbed methane reservoirs.We have analyzed China’s coalbed methane reservoir characteristics, accumulation, and the mechanism of gas migration and outputs, then proposed liquid powder fracturing technique for coalbed methane development in horizontal wells. This paper introduced the mechanism and technical advantages of liquid-powder high energy gas fracturing technology. This paper carried out the optimized design from four aspects respectively:liquid powder formulations, ignition process, isolation liquid preparation and operation process. Finally, a scheme design of liquid-powder high energy gas fracturing was given to the coalbed methane horizontal well called P-1in Qinshui Basin. This technology provides new ways for the exploratory development of coalbed methane resources in China. |
