UNS: Fluid-driven Fracture of Elastic Materials, Flowback Dynamics and the Effect of Proppants

1509347(斯通)拟议研究的目标是探索与水力压裂相关的流体动力学现象--水力压裂是一个对国内能源生产具有重要意义的领域。提出的这项工作是基于基本的理论分析和在简化的、非常好控制的明胶系统中进行的优雅的实验，以模拟弹性地质地层。当弹性材料水力破裂后压力释放时，流体可以回流。这是一个在水力压裂中发生的过程，对碳氢化合物的生产和环境都有影响，因为需要在地下监测水力压裂液。与流体驱动的弹性材料破裂相比，有大量的理论文献，但只有有限的实验，而关于释放压力控制注射时的回流的文献要少得多。这项建议是关于实验室实验和数学建模，以(I)了解和表征流体驱动的破裂的耦合流体流动和弹性应力，然后随着弹性应力的松弛而回流，(Ii)将这样做包括携带颗粒的流体(支撑剂)。这些实验将使用弹性但脆性的明胶材料，这种材料以前在固体地球物理文献中描述过，用于研究流体驱动的裂缝。因此，流体注入和回流与块状材料的弹性响应之间将存在联系，并使用适当比例的数量和量纲分析来解释结果。这些实验和建模工作将是第一批描述回流动力学和支撑剂作用的工作之一。研究生将参与研究，并将根据该项目的研究结果提供一系列外展讲座，即哈佛和普林斯顿大学为儿童和家庭举办的工程和科学假日讲座。

1509347 (Stone)The goal of the proposed research is to explore fluid dynamics phenomena that are related to hydraulic fracturing - an area of national importance for domestic energy production. The work proposed is based on fundamental theoretical analysis and elegant experiments conducted in simplified and very well-controlled systems of gelatin to model an elastic geological formation. When the pressure is relieved after hydraulic cracking of an elastic material, the fluid can flow back. This is a process that occurs in hydraulic fracturing and has implications for the production of hydrocarbons as well as for the environment, since hydraulic fracking fluids need to be monitored in the subsurface. In contrast to fluid-driven cracking of elastic materials, for which there is a substantial theoretical literature but only limited experiments, there is a much smaller literature on flowback when the pressure controlling injection is released. This proposal is about laboratory experiments and mathematical modeling to (i) understand and characterize the coupled fluid flow and elastic stresses of fluid-driven cracking followed by flowback as the elastic stresses relax, and (ii) will do so including a particle-laden fluid (the proppant). The experiments will make use of gelatin materials that are elastic but brittle and have been described previously in the solid-earth geophysics literature for the study of fluid-driven cracks. Hence, there will be a link between fluid injection and flowback to the elastic response of the bulk material, with results interpreted using appropriately scaled quantities and dimensional analysis. These experimental and modeling efforts will be among the first to describe the dynamics of flowback and the role of the proppant. Graduate students will be involved in research and a series of outreach lectures, the Harvard and Princeton holiday lectures on engineering and science for children and families, will be offered based on the research findings of the project.