煤储层多级强脉冲加载压裂破岩机理理论研究

Theoretical study of multi-level strong pulse loading fracturing mechanism of rock fragmentation in coal reservoir

针对我国煤储层"三低"的特性及煤气井单井产量较低的难题,研究多级强脉冲压裂技术的加载压裂破岩机理。依据岩石破裂的第一强度理论,建立力学模型,为多级强脉冲加载下的煤岩体破裂提供了理论依据。研究结果表明:火药在井筒中燃烧产生大量高温、高压气体不断往射孔孔眼中喷射,致使射孔孔眼内压力不断升高。当其压力大于煤岩体破裂压力时,煤储层发生破裂产生裂缝,煤储层压力得到释放,煤层气得到解吸,解吸的煤层气通过产生的裂缝形成有效的渗流过程,从而提高了煤层气井的单井产量。

Aimed at the ＂three low＂ characteristics of coal reservoir and the problem of low single gas well production, strong multistage pulse fracturing technology of loading the fracturing mechanism of rock fragmentation has been studied.According to the first strength theory of rock burst,mechanical model is set up and it provides a theoretical basis for coal and rock burst under the loading of in multistage strong pulse.The study shows gunpowder combustion produces a large number of high temperature and high pressure gas in well-bore and it jet perforation constantly,which lead to the pressure in perforation increasing.When the pressure is greater than the coal and rock burst,the coal reservoir fracture cracks and its pressure releases,which coal-bed methane get desorbed.Desorption of coal-bed methane formed effective seepage process through the cracks,which improve the single well production in CBM wells.