致密油储层岩石注水吞吐实验与多尺度动态网络模拟研究

Tight oil reservoir has poor petrophysical properties, small pore-throat radius and strong heterogeneity. The water-injection huff-n-puff is a potential method for effectively development of tight oil reservoir. A thorough studying on the multiscale coupling of pore-scale two-phase fluid flow and pressure propagation in water-injection huff-n-puff can further improve tight oil development. The project uses the rocks from the tight oil reservoir in the Lucaogou formation of Jimsar, Xinjiang as the research object, and carries out water injection huff-n-puff core experiments and dynamic network simulations. The coupling of the counter-current imbibition in the soak (shut-in) phase, the pore-scale oil-water flow in flowback phase, and the pressure propagation in each stage of water injection huff-n-puff are reasonably described using mathematical model, and the corresponding GPU-accelerated multiscale dynamic network simulation algorithm is realized and verified by core experiments. The digital core was obtained by micro-nano CT scan, and used for extracting and reconstructing the relatively large-scale pore-network model. The network model is used to simulate water injection huff-n-puff in tight oil rock using multiscale dynamic network modeling, and the effects of the pore-throat size distribution, oil viscosity, nonlinear fluid flow, pressure propagation and the surfactant containing injected-water on water injection huff-n-puff processes in tight oil rock will be analyzed. The research achievements will deepen the fundamental theory of water injection huff-n-puff for oil production in the tight oil reservoir, provide technical support for the effective development of tight oil, and provide analytical means for the invasion/flowback processes of injected-water in the reservoir, which is widely existing in oil field exploration and development.

致密油储层岩石物性差、孔喉半径小、非均质性强。注水吞吐是一种潜在的致密油有效开发方式，深入理解致密油藏注水吞吐采油过程中孔隙尺度渗流与宏观压力传播的多尺度耦合作用有助于进一步提高致密油藏注水吞吐开发效果。项目以新疆吉木萨尔芦草沟组致密油储层岩石为研究对象，开展注水吞吐采油实验和动态网络模拟研究。建立焖井阶段的逆向渗吸、返排阶段的孔隙尺度油水两相流与宏观压力传播的耦合数学模型，实现相应的GPU加速多尺度动态网络模拟算法并通过实验数据进行拟合验证。通过微-纳米CT扫描获取数字岩心，抽取并重构较大尺度的孔隙网络模型用于注水吞吐采油动态网络模拟研究，分析孔喉半径分布、原油黏度、非线性渗流、压力传播与含表面活性剂注入水等对致密油藏注水吞吐采油的影响规律。研究成果将深化致密油藏注水吞吐采油基础理论，为致密油的有效开发提供技术支持，也为油田勘探开发中广泛存在的注入水在储层中的侵入/返排过程提供分析手段。

致密油储层岩石物性差、孔喉半径小、非均质性强。注水吞吐是一种潜在的致密油有效开发方式，深入理解致密油藏注水吞吐采油过程中孔隙尺度渗流与宏观压力传播的多尺度耦合作用有助于进一步提高致密油藏注水吞吐开发效果。项目以新疆吉木萨尔芦草沟组致密油储层岩石为研究对象，开展注水吞吐采油实验和动态网络模拟研究。建立了孔隙网络油水两相流与宏观压力传播耦合的非稳态渗流数学模型，实现相应的GPU加速多尺度动态网络模拟算法并通过实验数据进行拟合验证。通过微-纳米CT扫描获取数字岩心，抽取并重构较大尺度的孔隙网络模型用于注水吞吐采油动态网络模拟研究，分析孔喉半径分布、原油黏度、压力传播与含表面活性剂注入水等对致密油藏注水吞吐采油的影响规律。研究成果将深化致密油藏注水吞吐采油基础理论，为致密油的有效开发提供技术支持，也为油田勘探开发中广泛存在的注入水在储层中的侵入/返排过程提供分析手段。