井壁和地层骨架力学稳定性分析和完井方式选择

Analysis of Mechanical Stability about Borehole and Skeleton for Well Completion Choice

通过对井壁力学稳定性、地层骨架出砂机理和判断方法等的分析,得出了地层力学稳定性和骨架出砂、防砂对完井方式选择的判断方法和标准:①可以通过Bradley井眼周围应力计算方法和Von·Mises剪切破坏理论法判定井眼是否会发生力学上的不稳定,从而作出裸眼完井或支撑井壁的完井方式的选择;②根据岩石破坏理论,当岩石的抗压强度小于最大切向应力时,井壁岩石不坚固,将会引起岩石结构的破坏而出砂,据此可判断在各种生产压差下地层骨架砂是否会遭到破坏,从而选择合适的防砂完井方式。同时,分析了注水、压裂、酸化、稠油、防砂方式、垂直或高陡角裂缝油层、层间压力差异大小等因素对力学稳定性分析的影响。

There are many modern completion methods ,but the selection of the method needs integrated consideration including whether wellbore is stable and the formation produces sand during production or not, the characteristics of geology and reservoir engineering,magnitude of completion productivity,cost of drilling cornpletion,the benefit of economic and production engineering,etc.In this paper,the factors of mechanics stability of wellbore ,mechanism of sand production are theoretically analyzed which derives the judgment standard of selection of completion method by mechanics stability and sand control,and summarizes many selection gists of completion methods under many conditions based on requirements of geology and engineering to guide exploitation and exploration of oil-gas field and increase economic benefits.