同步压裂时裂缝延伸规律

LAWS OF THE FRACTURE PROPAGATION FOR THE SIMULTANEOUS FRACTURING

同步压裂是对两口或两口以上基本平行的水平井的对应井段同时进行压裂施工,以期获得更好的单井产量、提高采收率。以边界元方法中位移不连续法为基础,根据岩石断裂力学,结合裂缝转向机理建立一个平面二维模型,模拟研究两口井同步压裂时裂缝的延伸,对比相同条件下单井压裂时裂缝的延伸情况,讨论缝内净压力和缝间距对裂缝延伸路径的影响。研究表明:在相同的条件下,同步压裂比单井压裂更容易使裂缝发生偏转;同步压裂时裂缝相互吸引、靠近,单井压裂时裂缝相互排斥、远离;缝内净压力对裂缝偏转的影响大于缝间距。该研究为致密油以及页岩气实施同步压裂提供了理论依据与参考。

The simultaneous fracturing is the stimulation that fractures two or more than two generally parallel corresponding intervals of the horizontal wells at the same time so as to obtain much better individual-well production and recovery factor. With the help of the displacement discontinuity method in the boundary element approach and the theory of rock fracture,and moreover integrated with the mechanism of crack reorientation,the planar 2D model was established to simulate the fracture propagation in the two simultaneously fractured wells. And then the fracture extension conditions were contrasted with the individual well fracturing in the same condition,and finally the influences of the net pressure inside the fractures and intervals among the fractures were discussed on the fracture spread paths. The achievements show that in the same condition,the fractures from the simultaneous fracturing are easy to deviate and deflect comparing with those of the individual well fracturing; for the former,the cracks attracts and approaches each other,but the latter is just on the contrary; the influences of the net pressures within the fractures are more those of the fracture deflection.