地下水封油库围岩多相渗流-变形耦合特性与水封机理研究

The water-sealing mechanism and its performance control in the surrounding fractured rocks of underground oil storage caverns is a key issue for the state strategic petroleum reserves, and also a frontier issue in the field of rock mechanics, which involves a number of key scientific subjects such as the cavern excavation-induced damage growth and permeability variation in the surrounding rocks, the oil-water-gas three-phase flow behaviors, the coupled multiphase flow and deformation processes and the performance assessment and optimization design of the water curtain system. Based on the principles of continuum mechanics, micromechanics and thermodynamics, this project focuses on the multiphase flow and its coupled behavior with deformation in the surrounding rocks of underground oil storage caverns, using a comprehensive methodology of laboratory tests, theoretical analysis, numerical simulations as well as in-situ monitoring and inverse modeling. The damage growth and its induced permeability variation will first be characterized in the surrounding rocks subjected to cavern excavation and pore fluid pressures. The oil-water-gas multiphase flow structures and behaviors in the surrounding rocks will then be examined, and the coupled mechanisms between the multiphase flow and deformation processes are to be demonstrated. A coupled multiphase flow and deformation model will be proposed, and a computer code will be developed for performance assessment and optimization design of the water curtain system installed in the surrounding rocks for effective control of oil/gas leakage. The research results are of great scientific significance in better understanding the multiphase flow and its coupled behaviors with deformation in the underground oil storage cavern systems, and also of important practical values in improving the construction and operation of the forthcoming large amount of underground oil storage caverns in China.

地下水封油库围岩水封机制及其性能调控是国家油/气能源战略储备的关键问题，也是国际岩石力学领域的前沿课题，涉及洞室群围岩开挖损伤效应与渗透特性演化、油-水-气多相渗流特性、渗流与变形耦合机理、水幕系统性能评估与优化等关键科学问题。本项目以连续介质力学、细观力学和热力学原理为基础，以地下水封油库围岩的多相渗流特性及其控制为主线，采用室内试验、理论分析、数值模拟和监测反馈相结合的方法，开展地下水封油库围岩开挖损伤效应及油-水-气多相渗流特性研究，阐明开挖与渗流耦合作用条件下围岩损伤及其诱发的渗透特性演化特征，揭示围岩油-水-气多相渗流特性及其与变形的耦合机制，建立围岩多相渗流-变形耦合模型与分析方法，研制水幕系统精细化模拟与优化设计分析平台。研究成果对于深化地下水封洞库系统多相渗流特性与水封机理研究具有重要理论意义，对于提升我国即将开展的大规模地下水封油库工程建设与管理水平具有重大应用价值。

本项目以地下水封油库洞室群围岩多相渗流特性及其过程控制为核心科学问题，开展地下储油库围岩开挖损伤机理与渗透特性演化、油-水-气多相渗流特性与模型、渗流-变形耦合机理与分析方法以及地下储油库水封机理与水幕系统优化设计方法等四个方面内容的研究。主要研究成果如下：.（1）提出了峡谷区结晶岩渗透性随埋深、风化、构造等因素的空间分布规律，建立了基于双尺度均匀化的岩体各向异性损伤模型及渗透特性演化张量模型，发展了考虑开挖扰动效应的岩体渗透张量多目标反馈分析方法，为地下水封洞库渗流场分析提供了关键参数和分析模型。.（2）分别建立了基于高压压水试验、抽水试验和统计分析的岩体非达西渗流参数辨识方法，发现了非达西渗流参数之间存在3/2幂次普适关系，提出了考虑非达西渗流效应的岩体防渗设计准则。成果被我国能源行业标准采纳，解决了非达西渗流从理论到应用的瓶颈问题。.（3）研发了多孔裂隙介质多相流可视化实验系统，发现了裂隙介质多相渗流的流动模式与能量耗散机制，提出了多相流界面失稳的临界判别准则，首次建立了裂隙多相流流动模式相图，系统揭示了裂隙粗糙度、湿润性及非均质性控制多相流流动结构的细观机制，为岩体宏观多相流模型的构建奠定了理论基础。.（4）建立了复杂渗流过程数值模拟的变分不等式统一分析方法，研发了岩土介质两相流与变形耦合数值分析平台，构建了基于子结构技术的地下水封洞库工程水幕系统精细模拟技术与优化设计方法，并依托我国黄岛地下水封油库，形成了基于安全指标、水力梯度和渗流量的水幕系统设计准则。.在本项目资助下，共计发表论文33篇，其中SCI收录29篇，EI收录4篇；获教育部科技进步一等奖1项；参编行业规程1部，授权国家发明专利2件，实用新型专利2件，软件著作权登记2项；项目负责人获国家杰青项目资助；培养博士研究生12名、硕士研究生14名，1篇博士学位论文入选全国高等学校水利类专业优秀研究生论文。