基于数字岩心和Peng-Robinson状态方程的孔隙级多相多组分渗流模拟研究

油-气-水多相多组分渗流是油气资源开发中的基本物理问题，如何实现对各相各组分分布的精确描述从而实现对带混溶渗流过程的准确模拟一直是油藏模拟领域的难点之一。申请人针对这一难题，在国际上首次提出了基于真实热力学状态方程的扩散界面模型，并在单通道内多液滴（气泡）的部分混溶多相多组分流动模拟中取得了一定成果。然而，由于储藏岩石结构比较复杂，加之孔道表面浸润性和相间部分混溶性对相对渗透率和毛管压力的影响机制尚不明确，孔隙级多相多组分真实渗流模拟依然存在巨大挑战。据此，本项目拟开展以下研究：（1）采用智能岩心技术，对复杂岩石结构及其热力学环境进行精确分析和三维重现；（2）发展真实热力学状态方程的高效求解技术；（3）基于真实热力学状态方程的扩散界面理论，建立复杂多孔介质多组分多相渗流模型。通过以上研究，最终构建一套新颖全面的基于数字岩心和Peng-Robinson状态方程的孔隙级多相多组分渗流模拟体系。

Oil-gas-water multi-component multiphase flow in porous media is one key problem in oil and gas engineering. Accurate description of component distribution in each phase and modeling of pore-scale porous media flow with partial miscibility are of great challenge in the field of reservoir simulation. To address with this problem, the applicant has established diffuse interface models based on the realistic thermodynamic equations of state for the first time in the literature; in addition, the applicant has published a series of papers on pore-scale multi-component multiphase flow simulation of multiple droplets (bubbles) with partial miscibility in a single channel. However, due to the complexity of reservoir rock structure, together with the complicated effects of wettability and partial miscibility on relative permeability and capillary pressure, the modeling and simulation of pore-scale multi-component multiphase flow are still far from its maturity and more efforts are needed. Based on this, we propose to carry out the following research tasks: (1) Using digital rock technology, we accurately analyze and create complex three-dimensional rock structures and reproduce their thermodynamic environment; (2) We investigate and derive efficient numerical techniques for realistic thermodynamic equations of state; (3) We develop diffuse interface theory based on the realistic thermodynamic equation of state (especially Peng-Robinson equation of state) to model complex flow in complex porous media. Finally, by combining these three aspects of research, we build a new framework of pore-scale multi-component multiphase flow with partial miscibility in complex rock structures.