定向井胶乳水泥石力学适应性有限元评价

Evaluation of Mechanical Adaptability of Latex Cement Paste for Directional Well Using Finite Element Method

水泥环力学完整性的分析基本是直井,定向井的水泥环力学适应性评价相对较少。通过建立套管-水泥环-地层系统三维有限元计算模型,对模型施加初始地应力场和温度场,针对开发的胶乳水泥浆体系,研究不同井斜条件下温压改变后固井水泥环力学完整性。研究结果表明:①随着试压压力和温度的增加,水泥石塑性区不断增加,等效塑性应变逐渐增加;②斜井段比水平段中的水泥环进入塑性的风险要小一些;③胶乳水泥体系抗内压值可达20.7 MPa,抗温可达220℃。针对不同地应力条件下的目标井进行水泥体系的配伍性设计,尤其在稠油热采井中具有良好的应用前景。

The analysis of mechanical integrity of cement sheath is basically aim at vertical wells,and the mechanical adaptability eval⁃uation of cement sheath of directional well is less.A three-dimensional finite element calculation model of casing-cement sheath-for⁃mation system is established,and the initial in-situ stress field and temperature field are applied to the model.The mechanical integri⁃ty of cementing cement sheath using the developed latex cement slurry system after temperature and pressure are changed under differ⁃ent well deviation conditions is studied.The results show that:(1)with the increase of test pressure and temperature,the plastic zone and the equivalent plastic strain of cement increase;(2)The risk of plastic deformation of cement sheath in inclined section is smaller than that in horizontal section;(3)The internal pressure resistance of latex cement system can reach 20.7 MPa and the temperature re⁃sistance can reach over 220℃.The conclusions of the study can be used to design the compatibility of cement system for target wells under different in-situ stress conditions,especially in heavy oil thermal production wells.