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

世界上碳氢化合物和淡水供应的很大一部分发生在裂缝穿过致密基质的地质构造中。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，人们付出了相当大的努力。虽然通常被认为是刚性管道，但岩石中的裂缝实际上具有一定的柔韧性，即使压力适度增加，裂缝也会张开，压力下降时裂缝也会缩小。在泵送过程中测量和解释排量和压力是流体机械试井的本质。压力和位移的测量可以用来确定含水层的储存量，仅使用抽水井的数据；传统的方法需要使用观测井来估计储气能力。该项目的目的是开发和完善进行和分析流体力学井测试的现场技术。该项目的动机是努力解决含水层特征、井况、节理地层和地球潮汐。拟议项目的知识价值包括三个主要领域的进展：a)裂缝流体力学的理论分析，b)现场技术和仪器，c)在裂隙岩石含水层下的现场应用和假设测试。该项目将生产可用于试井的便携式延伸计，并将开发新的理论分析，用于预测和反演流体机械试井期间获得的位移和压力信号。通过反演裂缝中流体流动和变形耦合的轴对称模型来估计距离抽油井一定距离处的非均质性是可能的。无论是作为一种独立的技术，还是作为一种与其他方法相结合的技术，流体力学井测试都为压裂岩石含水层的表征提供了前景。该项目将提供与地下水开采和修复、地热能、石油和天然气生产、深井注入处置危险废物、核废料处置库、地震和海啸预测、滑坡力学、岩石力学以及与裂隙岩石中流体流动和变形有关的各种其他学科相关的见解。该项目将启动克莱姆森大学和佐治亚理工学院之间的创新教育合作伙伴关系，为培养地质力学和水文地质学各个层次的学生提供独特的机会。此外，我们将启动一项计划，使中学地球科学教师每年夏天都能学习井测试知识，并为他们的学生带来井测试练习。

An important fraction of world supplies 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.