CARRER: Estimation of Fracture Aperture Distributions From Wellbore Data

9505773伦肖裂缝被认为是许多地下流动系统的重要组成部分。因此，对裂隙的水文地质特征的了解直接影响我们模拟废物分离、矿床成因、自然资源回收和含水层补救等重要社会问题的能力。在过去的十年里，许多研究人员使用理论、数值和实验方法试图了解单个裂缝的流动和运移特征。虽然这些研究者使用的裂缝几何的实验和概念模型各不相同，但每个研究者得出的基本结论是相同的：通过单个裂缝的流动和输运主要受裂缝平面内的裂缝孔隙控制，特别是裂缝孔隙分布的均值和方差。不幸的是，关于单个裂缝中裂缝孔分布的数据很少。此外，尚不清楚从地表暴露或实验室样品获得的裂缝孔数据在多大程度上代表了裂缝孔的现场分布，这些样品因爆炸而受到卸载和/或应力集中。因此，这项拟议工作的主要目标是开发和实验测试一种间接的、原位的裂缝孔分布。因此，拟议工作的主要目标是开发和实验测试一种间接的、原位的技术，用于根据三种不同类型的井筒数据来估计裂缝孔径的分布：直接孔径测量、水头测量和示踪剂到达时间。对于通过不渗透基质中非常简单的裂缝的流动和输送，所提出的估计方法被证明能够以合理的精度预测裂缝孔隙的分布。为了使这一过程适用于实际的裂缝，需要考虑示踪剂进入和吸附到裂缝壁和岩石基质中的可能性。还提出了在实验室规模的具有可测量孔径分布的样本上测试估计过程的方法。这种技术测试是将估算程序应用于现场数据的必要前提。拟议的研究是对教育目标的补充，因为两者都寻求进一步将工程水文地质学的工具和技术与更传统的地质分析相结合。例如，教育目标之一是重新设计水文地质学入门课程，以便更彻底地将该领域的工程和地质方面结合起来。这包括开发练习和交互式计算机实验室，要求学生在开始对系统的水文地质学建模之前解释和分析地质数据。此外，入门课程正在重新设计，以包括传统课程中找不到的许多最新的工程分析。这些讨论包括关于斜坡和断层稳定性、地质统计学、线性估计和不确定性以及优化和管理等主题的讨论。课程的目标不仅是展示现代水文地质学的许多不同方面，而且还为学生提供充分的背景知识，使他们能够将这些工具应用于水文地质学以外的其他地球科学领域的问题。

9505773 Renshaw Fractures are recognized as important component of many subsurface flow systems. Consequently, an understanding of the hydrogeologic characteristics of fractures directly affects our ability to model such important societal problems as waste isolation, ore deposit genesis, natural resource recovery, and aquifer remediation. Over the past decade, numerous investigators have used theoretical, numerical and experimental methods to attempt to understand the flow and transport characteristics of individual fractures. While the experimental and conceptual models of the fracture geometry used by each of these investigators differs, the basic conclusion reached by each is the same; that flow and transport through an individual fracture is primarily controlled by the fracture apertures within the fracture plane and , in particular, the mean and variance of the fracture aperture distribution. Unfortunately, little data are available on the distribution of fracture apertures in a single fracture. Further, it is unclear to what extent fracture aperture data obtained from surficial exposures or laboratory samples, which have been subject to unloading and /or stress concentrations due to blasting, represent the in situ distribution of fracture apertures. Thus the primary objective of the proposed work is to develop and experimentally test an indirect.in situ distribution of fracture apertures. Thus the primary objective of the proposed work is to develop and experimentally test an indirect, in situ, technique for estimating the distribution of fracture apertures based on three different types of wellbore data: direct aperture measurement, hydraulic head measurements and tracer arrival time times. For flow and transport through a very simple fracture in an impermeable matrix, the proposed estimation procedure is demonstrated to predict the distribution of fracture apertures with a reasonable degree of accuracy. In order to adapt this procedure to real fractures, the possible diff usion and sorption of the tracer into and onto the fracture walls and rock matrix needs to be considered. Testing the estimation procedure on a laboratory scale sample with a measureable aperture distribution is also proposed. Such a test of the technique is a necessary prerequisite for the application of the estimation procedure to field data. The proposed research complements the education objectives as both seek to further integrate the tools and techniques of engineering hydrolgeology with more traditional geological analyses. For example, one of the education goals is to redesign the introductory hydrogeology curriculum to more thoroughly integrate the engineering and geological aspects of the field. This includes the development of exercises and interactive computer-based laboratories which require the students to interpret and analyze geologic data before they begin to model the hydrogeology of the system. Additionally, the introductory course is being redesigned to include many of the more recent engineering analyses not found in traditional courses. These include discussions on such topics as slope and fault stability, geostatistics, linear estimation and uncertainty, and optimization and management. The goal is not only to demonstrate the many different aspects of modern hydrogeology, but also to give the students sufficient background that they might apply these tools to problems in other geoscience fields beyond hydrogeology.