| In order to enhance the production of horizontal well and improve the economic benefit of development,the multi-pulse gas loading fracturing on horizontal well is studied and applied and a relative stimulating soft ware is also developed to optimize the fracturing in this paper, which is of great significance for scientific research and field application . Based on the fracturing horizontal well technology need, the main achievements in this paper can be concluded as follows:(1) Analyzing the devices of multi-pulse gas loading fracturing and flame ignition that related to horizontal well,this paper designs reasonable propellant charge,analyses the characteristics of this technology and evaluates its secrity and reliability.(2) According to the theory of elastic mechanics and fracture mechanics under deflagration gas loading fracturing ,established the mathematical model of the stress field distribution around the horizontal well bore and the model of fracturing pressure and fracturing angle for open-hole and perforated well.The modeling can be solved and provides the reliable theoretical evidence for fracturing treatment of horizontal well.(3) Based on the flow behavior of deflagration gas in horizontal oil well, a theoretic model of detonation gas flow in preliminary crack is established, by means of introduction of a pressure distribution function concluded from analytic result of gas flow along the crack.(4) The crack opening displacement is also modeled by referencing relationship between crack normal displacement and pressure along the crack in multi-pulse gas loading fracturing model.The stress strength factor at the crack tip is deduced to estimate fracture initiation.Energy release rate obtained by J-integral at the crack tip is used to determine the crack spread velocity after fracture initiation. Coupling process between detonation gas flow and crack spread is also simulated based on the combination of the solid一fluid governing equations,which can be solved to moldeling the fracture geometry and pressure distribution along the fracture of each stage. As allow for rapid fracture process driven by detonation gas,kinetic energy increment is further introduced into energy conservation equation at the crack tip.(5) The results from this numerical model agree with corresponding results from half-analyzed and concrete column test. Aim at the fracture length which is main factor in oil well to relate the production, several primary factors are systematically discussed by numerical test to find out the most effective measures fracturing works. in horizontal well.This paper also derives the formulae to estimate the productivity increase achieved by muitiple fractures and discusses the main factor of influence.(6) The method of muti-pulse gas loading fracturing on horizontal well is disscussed,which studies the operating processes of this technique under down-hole condition and productivity contrast after fracturing to lay the groundwork for the future field application.
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