水泥环对套管应力影响的模拟与分析

Simulation and analysis of effect of cement ring on casing stress

固井施工以下套管和注水泥来建立油气安全生产通道,该安全通道由套管、水泥环和地层构成,而不同地层和水泥环环境会改变套管应力分布,影响油气安全生产。本文基于直井的地层-水泥环-套管耦合平面弹性应变模型,并借助ABAQUS有限元软件,分析了水泥环弹性模量以及水泥环缺失(包括周向缺失与径向缺失)对套管应力分布的影响,以期得到水泥环弹性模量及水泥环缺失对套管应力分布的影响规律。由于井下实际情况复杂,全实物模拟套管在井眼中所处的状况实属不易,本文借助有限元软件ABAQUS对井下套管应力分布进行了较为全面的模拟和分析。分析结果对固井后套管应力分布优化具有一定的参考价值。

Cementing job provides oilwell production with safe channel, which consists of casing and sheath as well as formation, however conditions with different kinds of formations and sheaths have effect on the distribution of casing stress, which is bad for the safety of oilwell production.So,based on formation-sheath-casing coupling system as well as previous related theories,this paper studied the distribution of casing stress.Depending on the plane-elastic stress theory,the paper based on the coupling formation-sheath-casing model,and resorted to the finite element software ABAQUS to analyse the effect on the distribution made by cement ring parameters,incluing cement ring elasticity modulus and cement ring missing, and the disciplines of each factorsleffects on the distribution of casing stress were attained. Cause of the intricate condition in wellbore,the FEM simulation aided by ABAQUS makes the simulation of the distribution more comprehensive and easier,which plays a guiding role in optimizing the distribution of casing stress.