气水交替驱油藏注入能力分析及优化

针对注入能力降低是制约气水交替驱提高油藏采收率的关键因素的问题，以相似理论中的检验分析法推导了气水交替注入无因次注入能力方程，运用考虑相渗和毛管滞后效应耦合的数值模拟方法，评价无因次注入能力的因素影响，讨论并优化了注入水气比。研究结果表明：对于特定油藏体系，通过增加注入气的富化度提高粘滞力重力比来达到改善驱替效果的方法比片面地增加注气速度更高一些；水气比越高，达到相同开采效果所需气量越小，但因此而出现较明显的注入能力下降的趋势。对于低粘滞力重力比的注气条件，选择水气比为2最佳；而对于高粘滞力重力比，则水气比为1是最佳选择。建议在水气比的优选时充分结合油藏地质特征和注入流体特性进行分析。

DYNAMIC ANALYSIS OF THE FRACTURE PROPAGATION BY MULTI-PULSE HEGF

Based on the flow behavior of the high energy gas in oil well，the mass and momentum conservation equations of high energy gas flow in fracture are established and the boundary conditions are defined.Besides，the distribution relationship between gas loading rate at the inlet of the fracture and the deflagration gas pressure are qualitatively analyzed by the semi-analytical method.Considering the dynamic response of crack tip，the fracture initiation and propagation under the function of high energy gas are analyzed based on the dynamic energy release rate analyzing method of the fracture mechanics.The fracture velocity and length can be obtained by iterative solution of dynamic energy release rate equation in every time step when loading rate is given，as well as the conditions of fracture initiation and arrest.In the case study，the results further show that dynamic response of high energy gas on fracture greatly influences the ultimate fracture propagation.Compared with quasi-static results，the dynamic process can provide a higher crack arrest pressure，earlier arrest of fracture and a much shorter fracture length.