关键词: 地层系数, 地层污染, 水力压裂, 产率比, 水平裂缝, 裂缝导流能力, 压裂液, 压裂效果, 计算公式, 污染程度

Abstract: In hydraulic fracturing,formation may be damaged in two ways,the damage near wellbore by such fluids a.s drilling mud befare fracturing and taae damage behind fracture faces by fracturing fluids after fxacturing.In this paper,a general formula of well productivity ratio has been developed,taking auaunt of the variations of the formation flow capacity and the conductivity of the propped fracture in horizontal fracturing,and has been applied to analyse the practical cases with the damages mentioned above as well as those with the tail-in process.Analyses and discussions axe made an the effects of the damage bath before and after fracturing on the evaluatian of the productivity xatia.A comparison with the electric analog modeling curves gives the conditions under which the presented faxnxulas in this paper can be applied.