Study And Application Of Prolongation Law Of Hydraulic Fracture For Directional Well

Base on the investigating of the directional well fracturing cracks and the law of crack extension at home and abroad,this paper analyzed the various factors affecting the impact fracture crack extension.Affected by natural fracture and angle of hydraulic fracture in the inclined shaft lining,there may be three kinds of crack,tensile crack along the natural fracture surface,respectively,from the rock bodies along the natural fracture plane shear fracture and crack.According to formation stress condition and natural fracture occurrence,established the fractured formation of hydraulic fracture of three slope crack crack way pressure calculation model,the proposed the way of hydraulic fracture crack and the crack stress of discriminant method.Analyzed the influence of perforation parameters on the fracturing fracture crack law,perforating wellbore geometry model was established and perforation crack stress and crack angle control equation,calculating perforating the wellbore stress distribution is analyzed,influence of perforating parameters on directional well fracturing fracture crack are studied.Considering vertical fluid pressure gradient,in-situ stress gradient and fluid gravity gradient,stress difference between reservoir and interlayer and influence factors of rock mechanics parameters,such as longitudinal crack extension,on the basis of analyzing composition of cracks in the wall stress characteristic,to establish the mathematical model and numerical calculation of longitudinal crack extension model,proposed the vertical and horizontal cracks crack criterion.Through analysis,the formation of rock fracture toughness of fracturing cracks vertical extension plays a significant role,rock fracture toughness,if large enough,will form an effective barrier layer limit fracture extension,ignoring the role of rock fracture toughness is bound to be on fracture height error of the prediction results is larger.Using established fracturing fracture crack extension mode,Xue Ping blocks of xue bifurcation oilfield has carried on calculation example,compared with data of Field fracturing operation data and micro seismic monitoring data,calculation precision of model is reliable.