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-这是国内能源生产的国家重要领域。提出的工作是基于基本的理论分析和优雅的实验进行了简化和非常好的控制系统的明胶模拟弹性地质构造。当弹性材料液压破裂后压力释放时，流体可以回流。这是在水力压裂中发生的过程，并且对碳氢化合物的生产以及对环境具有影响，因为需要在地下监测水力压裂流体。与弹性材料的流体驱动破裂相比，有大量的理论文献，但只有有限的实验，当压力控制注入被释放时，回流的文献要少得多。该提案是关于实验室实验和数学建模，以（i）理解和表征流体驱动破裂的耦合流体流动和弹性应力，然后在弹性应力松弛时回流，以及（ii）将包括载有颗粒的流体（支撑剂）。实验将使用明胶材料，这种材料是弹性的，但很脆，以前在固体地球物理学文献中已经描述过，用于研究流体驱动的裂缝。因此，流体注入和回流与散装材料的弹性响应之间将存在联系，并使用适当缩放的量和尺寸分析来解释结果。这些实验和建模工作将首先描述回流的动力学和支撑剂的作用。研究生将参与研究，并将根据该项目的研究结果举办一系列外联讲座，即哈佛和普林斯顿的儿童和家庭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.