Abstract: In the theoretical model research on complex perforation,domestic and international oil companies and relevant research institutions mainly place their concentration on deflagrate mechanism,fracturing mechanism of rock and formulation of the crack,however,the research on effect of surplus high energy gas and water hammer of control fluid is inadequate.The function characters of high energy gas and water hammer of control fluid after fracturing charge are studied and the motion differential equation derived in this paper,a mathematical model for evaluating bottom hole pressure is proposed,the change of wellbore pressure comprehensively studied,slug of control fluid,pulse action of high energy gas and water hammer after fracturing charge are studied in detail.Last,through an example computation,it is proved that water hammer of control fluid and pulse action of surplus high energy gas have positive function on the effect of complex perforation.

Key words: control fluid, gasliquid interaction, high energy gas, pulse action, mathematical model