This paper presents a hybrid numerical model for simulating compressible multiphase multicomponent transport in deformable, heterogeneous unconventional reservoirs. A fully implicit theoretical framework for coupled hydromechanical behaviour is established, in which the flash calculation is avoided. To preserve the local mass conversation, an element based finite volume method is used to spatially discretize mass conversation equations. Linear momentum equilibrium equation is discretized with finite element method. Two numerical approaches are coupled through sharing the same shape functions. An implicit mid-interval backwards difference algorithm is used to handle the temporal derivative. Reliability and efficiency of the developed model have been examined by verification tests against available analytical or numerical solutions. The coupled hydromechanical processes in heterogeneous reservoirs were simulated. The results of numerical experiments show that oscillatory problem for saturation in heterogeneous media can be eliminated, demonstrating better performance of developed model for heterogeneous reservoir simulations. Reservoir performance is significantly shaped by its heterogeneity through controlling fluid flow and time for CO–CH displacement. Simulation results show that the time required for completion of CO–CH displacement increases by about 250 days when considering heterogeneity effect. In conclusion, this study offers a valuable tool for facilitating the development of CO-enhanced unconventional gas recovery.

中文翻译：

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非常规油藏二氧化碳注入过程中耦合流体力学分析的混合数值模型

本文提出了一种混合数值模型，用于模拟可变形、非均质非常规油藏中可压缩多相多组分输运。建立了耦合流体力学行为的完全隐式理论框架，避免了闪蒸计算。为了保留局部质量对话，使用基于单元的有限体积方法对质量对话方程进行空间离散。采用有限元方法对线性动量平衡方程进行离散化。两种数值方法通过共享相同的形函数而耦合。使用隐式中间隔向后差分算法来处理时间导数。所开发模型的可靠性和效率已通过针对可用分析或数值解决方案的验证测试进行了检验。对非均质油藏中的耦合流体力学过程进行了模拟。数值实验结果表明，可以消除非均质介质饱和度的振荡问题，证明所开发的非均质油藏模拟模型具有更好的性能。通过控制流体流量和 CO-CH 驱替时间，储层性能受到其非均质性的显着影响。模拟结果表明，考虑非均质性效应时，完成CO-CH置换所需的时间增加了约250天。总之，这项研究为促进二氧化碳强化非常规天然气采收率的发展提供了一个有价值的工具。