水平应力作用下套管井不同胶结状况导波的声弹效应

油田的套管完井常伴有异常地应力的作用,对于套管井,井孔-套管-水泥环-地层组合的系统使井周的应力集中更为复杂.为认识地应力作用下不同胶结状态的套管井导波声弹效应,本文基于非线性声学理论,实现了受应力作用不同胶结状态套管井井周应力和径向横波速度计算与分析;采用摄动求解推导了套管井导波的声弹性方程,模拟并分析由应力引起不同胶结状态套管井斯通利波、伪瑞利波、弯曲波相速度的变化.研究结果表明:不同胶结状态会改变井周的应力分布,当界面出现滑移时井周地层中的应力集中有所增强,从而影响导波的声弹效应.本文的研究结果为地应力作用的套管井的声场特性提供认识和理论依据.

Acoustoelastic effects on guided waves in cased borehole with horizontal stresses

The stress concentration appears more complex for casing-cement-formation system with the abnormal stresses. We studied and analyzed the acoustoelastic effects of guided waves in a cased-hole under the horizontal stress with different bonding condition on the basis of the nonlinear acoustics. First, the velocity dispersions formulas are given with different bonding condition based on perturbation solution. Then, we accomplished the calculation and analysis of the stresses and radial shear velocities around the cased hole under horizontal stress; Finally, we simulated and analyzed the changes of guided wave velocities (Stoneley waves, pseudo-Rayleigh waves and flexural waves) due to applied stresses. The results show the characteristics of guided waves are affected by both horizontal stress and bonding condition.