A Study of Fracture-Induced Coupling Phenomena in Rocks

摘要CMS 9523072 PI：Kemeny，亚利桑那大学 耦合现象在岩石中极为重要，包括机械、水力、热力和化学过程。 在这项研究中，裂纹引起的耦合机制将调查与实验和建模研究。 重点将是如何调查的机械负荷，热负荷，和化学的流体环境中的裂缝影响岩石的流动性能。 实验重点将放在一系列耦合的机械/流动三轴试验中，测量轴向和横向渗透率，而样品受到三轴应力和过去的峰值应力。 实验室测试还将涉及热负荷（均匀加热和钻孔加热）和研究不同流体化学条件下裂纹扩展的测试。 建模将集中在有限元损伤模型的发展。 将在耦合机制之间建立基于断裂力学的关系，并将包括裂纹相互作用效应。 这些关系将被实施到一个有限元模型，以预测在复杂的边界条件下的耦合行为。 此外，将开发离散裂纹边界元模型，以研究由于热负荷和不同流体化学条件（通过亚临界裂纹扩展）导致的裂纹扩展能力，并将增加计算通过生成的裂纹群的渗透率的能力。

ABSTRACT CMS9523072 PI: Kemeny, University of Arizona Coupling phenomena are extremely important in rocks and include mechanical, hydraulic, thermal, and chemical processes. In this study, crack-induced coupling mechanisms will be investigated with both experimental and modeling studies. The focus will be on investigation of how mechanical loading, thermal loading, and the chemistry of the fluid environment in the cracks influences the flow properties of the rock. Experimental emphasis will be placed on a series of coupled mechanical/flow triaxial tests in which both axial and lateral permeabilities are measured while samples are subjected to triaxial stresses up to and past peak stress. Laboratory tests will also involve thermal loading (both uniform and borehole heating) and tests to study crack growth under different fluid chemistries. Modeling will be focused on development of a finite element damage model. Fracture mechanics-based relationships will be developed between the coupling mechanisms, and will include crack interaction effects. These relationships will be implemented into a finite element model to predict coupled behavior under complex boundary conditions. In addition, a discrete crack boundary element model will be developed to study the capability of crack growth due to thermal loading and under different fluid chemistries (via subcritical crack extension), and the capability of calculating the permeability through a generated crack population will be added.