高压注水引起热应力、泥岩蠕变对套管影响

The Effect of Thermal Stress and Mudstone Creep Caused by High Pressure Water Flooding on Casing

认识到油藏和注入水之间的温差对地层内部应力都有一定影响,以及高压注水导致泥岩蠕变,会引起的附加载荷挤压套管,套管发生了缩径变形,严重影响了注水效果。采用ANSYS软件,分别对热应力影响和泥岩蠕变的影响建立三维有限元数值分析模型。对模型求解,得到原始地层应力与注水后的应力变化规律,和井眼周围泥岩蠕变附加载荷和套管缩径变形规律。发现注入水温度高有可能使地层内部地应力呈增加趋势,对减少套损、提高注水效率具有一定的指导意义。

Recognize that the temperature difference between the reservoir and injected water has a certain impact on formation internal stress,as well as mudstone creep caused by high-pressure water flooding will cause additional load to extrude casing,result in necking deformation.Using ANSYS software,three-dimensional finite element numerical analysis models were created for studying thermal stress effect and mudstone creep effect separately.Solve the model,the original formation stress and the stress variation after water flooding was obtained,as well as the additional loads around the borehole and casing necking deformation law.It has certain guiding significance for reducing casing damage,and improving the efficiency of water injection.