变形介质影响下低渗透油田压裂水平井产能分析

PRODUCTIVITY ANALYSIS OF FRACTURED HORIZONTAL WELL IN LOW-PERMEABILITY OIL RESERVOIRS INFLUENCED BY DEFORMABLE POROUS MEDIA

文献调研显示，对低渗透油藏压裂水平井产能研究很少同时考虑启动压力梯度和应力敏感的影响。基于复位势理论和叠加原理，在油藏与井筒耦合模型的基础上，通过优化裂缝流动压降模型，综合考虑启动压力梯度和应力敏感的影响，得到低渗透油藏压裂水平井的产能方程，并分析了裂缝间距、裂缝半长、井筒半径、启动压力梯度和变形系数对水平井产能的影响。结果表明：在油藏参数一定的条件下，裂缝间距与裂缝半长均存在最优范围，在此范围内水平井产能最佳；启动压力梯度和变形系数对水平井产能影响显著，随2者值的增加，水平井产量急剧下降，因此低渗透油藏压裂水平井产能分析必须综合考虑2者的影响。

The document investigation shows that the influences of the threshold pressure gradient and stress sensi- tivity are seldom considered simultaneously in the productivity study of fractured horizontal well in low-permeability oil reservoirs. Based on complex potential theory, superposition principle and the coupled mode between the reser- voir and wellbore, the productivity formula of the well is established by means of the optimized model of fracture flow pressure drop and comprehensively considered influences of the threshold pressure gradient and stress sensitivi- ty ; the effects of some influencing factors such as fracture interval, fracture half length, wellbore radius ~ threshold pressure gradient, and deformation coefficient are analyzed. The results show that under the conditions of a certain reservoir parameters, there are the optimal ranges for fracture interval and fracture half length, the above productiv- ity is also optimal in this scope; the effects of the threshold pressure gradient and deformation coefficient on hori- zontal-well productivity are obvious and significant. With the rise of the gradient and coefficient, the production of the horizontal well drops rapidly, so the influences of above two parameters must be comprehensively considered for the analysis of the productivity of the fractured horizontal well in low-permeability oil reservoirs.