Research On Perforation-intense Pulsed Fracturing In Low Permeability CBM Reservoir

As a kind of clean energy,coal-bed methane(CBM)has a broad market to ease the tight supply of oil and gas.The economic development of CBM has great significance for China,because of its rich coal-bed gas resources.However,the technological development of CBM can not fully meet the requirements,because the domestic coal-bed features low permeability?pressure and saturation,which are the difficulties in the development of CBM reservoir,so urgently need to develop new technology.Therefore,based on the mechanism of high energy gas fracturing and its application in CBM reservoir,this paper focus on perforation-intense pulsed(complex perforation)fracturing mechanism in low permeability CBM reservoir.This paper established a mathematical model in dual media for CBM reservoir through the study of the structure of coal-bed and CBM migration mechanism,we can find that increase of the fracture permeability has a more apparent effect on the production rate and cumulative production.Based on the mechanism of high-energy gas fracturing technology,the whole sealing fracturing technology of CBM can be designed,which can increase the total charge and the ratio of energy utilization.Combined with the well test,which can improve about 0.6 to 1.3 times of energy utilization compared to open well.Provide theoretical guidance for the design of complex perforation process.Based on the mechanism of complex perforation and the features of coal-bed reservoir,design the process of complex perforator,including perforating bullet,the thickness of the blind hole,strength of the structure and explosive charge and calculate.The calculation model of the fracture length in coal-bed reservoir by the P-T curve of complex perforation,in order to calculate conveniently,the software is complied.This technology was applied to the construction site and achieved a successful process.The research of this technology is of importance method for the low permeability CBM reservoir development in China and have a good application prospect.