地应力和油藏压力对弱胶结砂岩油藏出砂的影响

借助岩石力学的基本理论,结合弱胶结油藏的岩石学特征,系统地分析了原地应力、生产压差等因素对弱胶结砂岩油藏出砂的影响,并对防砂技术和措施进行了讨论。结果表明:在弱胶结砂岩地层,地应力的非均匀性将导致某些方位地层先于其它方位地层剪切屈服、出砂,因此,对这些方位进行选择性避射将有助于防砂和延长油井开采寿命;当井筒内压力保持不变时,随着油藏压力衰竭,射孔孔眼发生剪切屈服、出砂的可能性增大;当地层压力恒定时,随着开采压差的增大,射孔孔眼发生剪切屈服、出砂的可能性随之增大。

THE EFFECT OF IN-SITU HORIZONTAL STRESSES AND RESERVOIR PRESSURE ON SAND PRODUCTION IN WEAKLY CONSOLIDATED SAND FORMATIONS

On the basis of rock mechanics, the effects of in-situ hori-zontal stresses and producing pressure drop on sand production in weakly-consolidated sand formations are analyzed, and tech-nique and measures of sand control for such formations are disc-cussed. It is shown that some areas around the borehole experi-ence shear failure and sand production much more easily thanothers as a result of inhomogeneous in-situ horizontal stresses.Therefore, it would help sand control to avoid perforating such areas in selecting perforation sites. In addition, when borehole pressure is kept constant, the possibility of shear failure of per-foration holes and sand production increases with the depletion of reservoir pressure; when formation pressure is kept constant,the possibility of shear failure of perforation holes and sand pro-duction increases with the increase of producing pressure drop.