| Low production of coalbed methane(CBM)of horizontal wells is the main problem on the CBM development in China.Thus the paper puts forward technical theory of screen completion and staged pressure stimulation of CBM horizontal wells.In this technology,the open packer is used to segment the coal and screen,and the volume fracture is formed by the interaction of cyclic shock wave technology and cyclic hydraulic stimulation technology.This paper mainly focuses on the mechanism of rock breaking and the law of fracture propagation.Therefore,the paper studied the technical mechanism of hydro-stimulated rock,the law of rock breaking under cyclic shock wave,the law of fracture propagation under cyclic hydro-stimulation pressure and the law of fracture propagation under cyclic shock wave intervention in hydro-stimulation rock breaking by theoretical analysis and numerical simulation.The main conclusions are as follows:(1)The structural coal bedding of Taiyuan formation in Qin shui basin has a significant influence on the anisotropy of the mechanical and physical characteristics of coal rocks,and the complex fracture system makes the coal matrix more sensitive to pressure than the coal bedding.(2)The screen completion and staged pressure stimulation of CBM horizontal wells includes screen completion technique,circulation shock wave technology and circular hydraulic stimulation technology,the cracks formed in the coal and rock reservoir volume,so as to realize increased permeability,production purpose.(3)The technical parameters of the cyclic shock wave have an important influence on the rock-breaking.The optimal technical parameters can improve the operation efficiency,reduce the damage to the reservoir,and achieve the best effect of the coal-rock reservoir reconstruction.(4)This technology can effectively reduce the fracture pressure of coal rock and form volumetric fracture through the mutual promotion of cyclic shock wave technology and cyclic hydraulic stimulation technology. |
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