Analytical formulation of nonisothermal injection in geological reservoirs remains challenging, and researchers have adopted a number of simplifying assumptions to theoretically predict the resulting geomechanical alterations. One common assumption behind current thermo‐poroelastic solutions is a constant temperature and constant pore pressure in the reservoir rock adjacent to the source/sink, which results in an unrealistic discontinuity in the rock temperature profile, ignoring the gradual geomechanical changes at this location. Another common assumption in previous studies is the plane strain approximation, thus ignoring vertical interactions between the target layer and the surrounding rocks. This paper presents new closed‐form thermo‐poroelastic solutions for nonisothermal injection in a low permeable porous layer confined with flexible sealing rocks. The transient nature of temperatures in the rock adjacent to the source/sink is incorporated through implication of a temporal heat and fluid flux boundary condition. The impact of vertical confinement is also integrated using the Winkler model. The proposed solutions are proven to capture generation of short‐term thermal‐induced pore pressures near the wellbore, which cannot be captured using conventional solutions. It is also demonstrated that the conventional solutions obtained using constant pore pressure and temperature boundary are in fact a special case of the proposed solutions, and the latter yield the former where the heat transfer between the source/sink and the rock occurs quite rapidly. The vertical confinement is also shown to have a notable impact on the induced stresses‐strains, and thus should be incorporated when studying wellbore stability or assessing seal rock integrity during nonisothermal injection.

中文翻译：

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挠性密封介质限制下的低渗透层在时间通量下的热孔隙弹性

地质储层中非等温注入的分析公式仍然具有挑战性，研究人员采用了许多简化的假设来从理论上预测由此产生的地质力学变化。当前热-孔隙弹性解背后的一个常见假设是，与源/汇相邻的储层岩石中的恒定温度和恒定孔隙压力，这导致岩石温度剖面不切实际的不连续，而忽略了该位置处逐渐的地质力学变化。先前研究中的另一个常见假设是平面应变近似，因此忽略了目标层与周围岩石之间的垂直相互作用。本文提出了一种新的封闭形式的热多孔弹性解，用于非等温注射在密闭柔性岩石限制的低渗透性多孔层中。通过隐含瞬时热量和流体通量边界条件，可以确定邻近源/汇的岩石中温度的瞬态性质。垂直约束的影响也使用Winkler模型进行了整合。实践证明，所提出的解决方案可捕获井眼附近短期热致孔隙压力的产生，而常规解决方案则无法捕获这些压力。还证明了使用恒定孔隙压力和温度边界获得的常规解决方案实际上是所提出解决方案的一种特殊情况，后者产生前者，其中源/汇和岩石之间的热传递发生得非常快。垂直限制也显示出对诱导应力应变的显着影响，因此在研究井筒稳定性或评估非等温注入过程中的密封岩完整性时应将其纳入考虑。