A Theoretical Study on the Governing Laws for Fluid Transport in Rough Fractures

粗糙裂缝中流体输运规律的理论研究

• 批准号: 9804789
• 负责人: Shemin Ge
• 金额: $ 15.05万
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-07-15 至 2002-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9804789&HistoricalAwards=false
• 关键词: Theoretical; Study; Governing; Laws; Fluid

9804789GeNatural rock fractures exist at all scales in the earth's upper crust. They play a major role in groundwater movement, solute transport, and waste isolation in geologic media. Characterizing fluid flow and mass transport in fractured rocks depends on our knowledge of how fluid transports through individual fractures. Yet fluid flow in fractures bounded by two rough surfaces is complex. Important questions on the validity of the cubic law and the Reynolds equation for rough fractures have been studied by many. The general conclusions are that the cubic law can only provide a qualitative description of flow rate, the Reynolds equation is not valid for rough fractures and effects of aperture and tortuosity need to be included in better governing flow laws. The primary goals of this research are (1) to systematically explore and quantify the effects of fracture roughness, tortuosity, and the formation of flow channeling on governing flow laws, and (2) to develop a better governing flow law for rough fractures by understanding the fluid transport mechanisms. Specifically, I will attempt to achieve the following objectives: (1) develop a rational method to characterize fracture geometry of natural rocks, (2) investigate the formation of channelized flow paths in generated and profiled fractures, (3) examine the conditions under which the modified Reynolds equation is valid, (4) identify the transitional flow regime from Darcian to non-Darcian flow, and (5) construct a better governing law that captures the dominant features of fluid transport in rough fractures. I will employ an array of theoretical approaches and utilize the existing lab experimental data to achieve these objectives. The Reynolds equation, the modified Reynolds equation including geometric variables of local aperture and tortuosity, and the Navier-Stokes equations will be solved numerically to simulate fluid flow in rough fractures. The Lattice Boltzmann method will be used for simulating both linear and non-linear fluid transport in fractures with complex geometries. The proposed research represents a comprehensive theoretical attempt to examine the governing laws for fluid transport in rough rock fractures.

9804789节岩骨折在地球上皮的所有尺度上都存在。 它们在地质媒体中的地下水运动，溶质运输和隔离中发挥了重要作用。 表征流体流量和骨折岩石中的质量转运取决于我们对流体如何通过单个裂缝传输的知识。 然而，由两个粗糙表面界定的裂缝中的流体流很复杂。 许多人都研究了有关立方法和雷诺方程的有效性的重要问题。 总体结论是，立方定律只能提供对流量的定性描述，雷诺方程对于粗糙的裂缝无效，并且需要包括在更好的管理流量法则中。 这项研究的主要目标是（1）系统地探索和量化断裂粗糙度，曲折度和流动渠道对管流律的形成的影响，以及（2）通过了解流体运输机制来为粗糙的裂缝制定更好的管理流量法。 Specifically, I will attempt to achieve the following objectives: (1) develop a rational method to characterize fracture geometry of natural rocks, (2) investigate the formation of channelized flow paths in generated and profiled fractures, (3) examine the conditions under which the modified Reynolds equation is valid, (4) identify the transitional flow regime from Darcian to non-Darcian flow, and (5) construct a better governing law that captures the裂缝中流体转运的主要特征。 我将采用一系列理论方法，并利用现有的实验室实验数据来实现这些目标。 雷诺方程，修改的雷诺方程，包括局部孔径和曲折的几何变量以及Navier-Stokes方程的数值求解，以模拟粗糙断裂中的流体流动。 晶格Boltzmann方法将用于模拟具有复杂几何形状的裂缝中的线性和非线性流体转运。 拟议的研究代表了一项全面的理论尝试，以检查粗糙岩石裂缝中流体运输法律的法律。