水泥环性质对套管破坏的影响分析

为研究水泥环受力对套管的影响,采用多孔介质流固耦合有限元计算方法和套管破坏准则,将地层和水泥环视作多孔介质,分析其对套管破坏的影响。通过建立地层-套管-水泥环有限元模型,对比研究套管在正常固井和未固井时所受的有效应力,定性分析水泥环材料性质对套管破坏的影响。研究结果表明:在多孔介质流固耦合作用下,水泥环对套管具有一定的保护功能;水泥环的泊松比对套管破坏影响较小;相较于其他两种水泥类型,膨胀水泥的性能更优,有效地减小了套管受到的应力应变。根据计算结果的分析,为套管的防护提供参考依据。

Analysis of the Influence of Cement Ring Properties on Casing Failure

In order to study the influence of the force of the cement ring on the casing,the fluid-solid coupling finite element method and the casing failure criterion of the porous medium were used to analyze its influence on the casing damage,in which the formation and the cement ring were treated as a porous medium.By establishing the formation-casing-cement ring finite element model,the effective stress of casing during normal cementing and uncementing was compared,and the influence of cement ring material properties on casing failure was analyzed qualitatively.The results showed that under the fluid-solid coupling effect of porous media,the cement ring played a certain protective role on the casing;the Poisson's ratio of the cement ring had less influence on the casing damage;compared with the other two cement types,the expanded cement had better performance,which can effectively reduce the stress and strain of the casing.According to the analysis of the calculation results,it provided a reference for the protection of the casing.