Quantifying the Link Between the Mechanical Controls on Fracture Formation and Network Permeability Using a Physically-Based, Three Dimensional Model of Fracture Growth

使用基于物理的裂缝生长三维模型量化裂缝形成的机械控制与网络渗透率之间的联系

• 批准号: 9814121
• 负责人: Carl Renshaw
• 金额: $ 17.33万
• 依托单位: Dartmouth College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-09-01 至 2003-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9814121&HistoricalAwards=false
• 关键词: Quantifying; Link; Between; Mechanical; Controls

9814121RenshawAlthough it is well known that fractures play an important role in petroleum exploration and production, waste isolation, aquifer remediation, and water resource management, our quantitative understanding of the impact of fracture networks on fluid flow remains limited. For example, existing fracture permeability models yield inconsistent results, even for simple network geometries. We hypothesize that the physical parameters controlling fracture growth can be used to better constrain the permeability of fractured rock. Accordingly, we seek to gain insight into flow through fractured rock via detailed numerical experiments designed to characterize the fundamental mechanical controls on three dimensional fracture formation. To accomplish these experiments, we propose to extend an existing, experimentally verified two-dimensional model of fracture growth to three dimensions. Once complete, the model will be used to address three fundamental questions: 1) What is the impact of mechanical layer thickness on network permeability? 2) How is fracture geometry and network permeability affected by strain rate? and 3) Do fracture mechanics parameters exert as strong an effect on the geometry and permeability of three dimensional fracure network as they do in two dimensions? In answering these questions the parameter space for which existing fracture permeability models are valid will be defined and criteria for selecting an appropriate permeability model established. Our results will provide the basis for more accurate analyses of the effects of fractures on fluid flow and establish the foundation for quantitative links between the physical properties of fractured rock and the engineering parameters required for reservoir simulation. The proposed work will also provide insight into the three dimensional geometric characteristics of fracture systems which may aid in development of improved fracture permeability models. Ultimately, we seek identify a limited set of physical parameters that can be both measured, either in the laboratory or the field, and used to contrain the three dimensional distribution of fracture permeability. Although mostly theoretical, our previous work demonstrates that our approach provides the framework for the enhanced interpretation of field data. In addition, our work will increase our general understanding of the failure of brittle materials. Consequently, results from this work will have broad application both within the earth sciences (e.g., earthquake mechanics) and beyond e.g., materials science and structural engineering).

虽然众所周知，裂缝在石油勘探和生产、废物分离、含水层修复和水资源管理中发挥着重要作用，但我们对裂缝网络对流体流动的影响的定量了解仍然有限。例如，现有的裂缝渗透率模型产生的结果不一致，即使对于简单的网络几何结构也是如此。我们假设，控制裂缝发育的物理参数可以用来更好地约束裂隙岩石的渗透率。因此，我们试图通过详细的数值实验来洞察裂隙岩石中的流动，这些实验旨在描述三维裂隙形成的基本力学控制。为了完成这些实验，我们建议将现有的、经过实验验证的二维裂缝生长模型扩展到三维。一旦完成，该模型将被用来解决三个基本问题：1)机械层厚度对网络渗透率的影响是什么？2)应变率如何影响裂缝几何形状和网络渗透率？3)裂隙力学参数对三维裂隙网络的几何形状和渗透率的影响是否与对二维裂隙网络的影响一样大？在回答这些问题时，将定义现有裂隙渗透率模型适用的参数空间，并建立选择合适的渗透率模型的标准。我们的结果将为更准确地分析裂缝对流体流动的影响提供基础，并为裂隙岩石的物理性质与油藏模拟所需的工程参数之间的定量联系奠定基础。这项拟议的工作还将深入了解裂缝系统的三维几何特征，这可能有助于开发改进的裂缝渗透率模型。最终，我们寻求确定一组有限的物理参数，这些参数既可以在实验室测量，也可以在现场测量，并用于测量裂缝渗透率的三维分布。虽然主要是理论上的，但我们以前的工作表明，我们的方法提供了加强现场数据解释的框架。此外，我们的工作将增加我们对脆性材料破坏的一般理解。因此，这项工作的成果将在地球科学(例如地震力学)和材料科学和结构工程之外得到广泛的应用。