Collaborative Research: Characterization of Fractured Rock Aquifers Using Hydromechanical Well Tests

全球碳氢化合物和淡水供应的一大部分出现在地质构造中，裂缝穿透了紧密的基质。可以理解的是，为了了解这些流体是如何沿着裂缝储存和通过孔隙空间传输的，人们已经付出了相当大的努力。虽然通常被认为是坚硬的管道，但岩石中的裂缝实际上在某种程度上是顺应的，即使是轻微的压力增加，裂缝也会张开，当压力下降时，裂缝会收缩闭合。在抽水过程中测量和解释位移和压力是水力机械试井的本质。压力和位移的测量可以用来确定含水层的储水量，只使用抽水井的数据；传统方法需要使用观察井来估计储水量。该项目的目的是开发和改进进行和分析水力机械试井的现场技术。该项目的动机是努力解决含水层特征、油井性能、联合形成和固体潮问题。拟议项目的智力优势包括在三个主要领域取得的进展：a)裂缝水力学的理论分析，b)现场技术和仪器，c)现场应用和裂隙岩石含水层下伏地点的假设检验。该项目将在可在试井期间使用的便携式伸长仪方面产生创新，并将开发新的理论分析，以预测和反转在水力机械试井期间获得的位移和压力信号。可以利用裂缝中流体流动和变形耦合的轴对称模型来估计距抽油井一定距离处的非均质性。水力机械井测试提供了希望，既是一项独立的技术，也是一项在描述裂隙岩石含水层特征方面与其他方法相结合的技术。该项目将提供有关地下水生产和修复、地热能、石油和天然气生产、通过深井注入处理危险废物、核废物在储存库中的处理、地震和海啸预测、滑坡力学、岩石力学以及与裂隙岩石中的流体流动和变形有关的各种其他学科的深入见解。该项目将启动克莱姆森和佐治亚理工学院之间的创新教育伙伴关系，为所有级别的学生提供独特的培训机会，学习地质力学和水文地质学。此外，我们还将启动一个项目，让中学地球科学教师每年夏天都能了解试井知识，并为学生带来试井练习。

An important fraction of the worlds supply of hydrocarbons and fresh groundwater occurs in geologic formations with fractures cutting through a tight matrix. It is understandable that considerable effort has been put into efforts to understand how these fluids are stored and transmitted through the pore spaces along fractures. Although commonly viewed as rigid conduits, fractures in rock are actually somewhat compliant, gapping open in response to even modest increases in pressure and shrinking closed when pressure drops. Measuring and interpreting both displacement and pressure while pumping is the essence of a hydromechanical well test. Measurements of both pressure and displacement can be used to determine the storativity of an aquifer using data from a pumping well alone; conventional methods require using an observation well to estimate storativity. The purpose of this project is to develop and refine field techniques for conducting and analyzing hydromechanical well tests. The project is motivated by efforts to address aquifer characterization, well performance, joint formation, and Earth tides. The intellectual merit of the proposed project includes advances in three primary arenas: a) theoretical analyses of fracture hydromechanics, b) field techniques and instrumentation, c) field applications and hypothesis testing at sites underlain by fractured rock aquifers. The project will produce innovations in portable extensometers that can be used during well tests, and new theoretical analyses will be developed for predicting and inverting displacement and pressure signals obtained during hydromechanical well tests. It is possible to invert an axisymmetric model of coupled fluid flow and deformation in fractures to estimate heterogeneities at some distance from the pumping well. Hydromechanical well tests offer promise, both as a technique that stands alone and as one that is integrated with other methods in the characterization of fracture rock aquifers. This project will provide insights that cut across fields related to groundwater production and remediation, geothermal energy, oil and gas production, disposal of hazardous wastes by deep well injection, disposal of nuclear wastes in repositories, earthquake and tsunami prediction, landslide mechanics, rock mechanics, and a variety of other disciplines concerned with fluid flow and deformation in fractured rock. The project will initiate an innovative educational partnership between Clemson and Georgia Tech that will provide unique opportunities for training students at all levels in geomechanics and hydrogeology. Furthermore, we will initiate a program to enable middle school earth science teachers each summer to learn about well testing and bring well testing exercises to their students.