Fracture and Transport Problems for Inhomogeneous Brittle Materials

非技术总结该奖项支持理论和计算研究，以及将理论材料研究与理解水力压裂中极端条件下导致材料断裂的物理过程相关联的教育，并有助于理解天然气和石油的生产。被称为水力压裂或水力压裂的技术已经使用了几十年，但在目前的形式下，它只有十多年的历史。这种技术发展对美国的影响是巨大的。在过去的5年里，美国经济的收益远远超过了1万亿美元，美国已经成为世界上最大的石油和天然气生产国。从页岩中生产石油和天然气似乎是自相矛盾的。页岩是已知的最不透水的材料之一。任何东西都不应该流经它们。那么，他们如何才能生产出革命性的天然气和石油呢？答案是，水力压裂过程会刺激它们，形成裂缝网络，这些裂缝必须以足够的间距分布，才能使生产成为可能。本项目将研究导致裂缝网络的物理过程。研究的一部分将涉及裂缝是如何形成的。这项研究的一部分将涉及如何利用地表产生的气体的时间历史线索来理解裂缝网络。这项研究的一部分将涉及石油和水如何在非常不均匀的岩石中流动。为了从这项工作中获得广泛的影响，PI将研究如何通过检查导致最大产量的油井的因素，并开发预测油井、气田和油田动态的方法，使这项研究具有可行性。国际和平研究所还将研究这些发现对向可再生能源过渡的影响。国际和平研究所有许多机会将研究与教育和外联相结合。该协会管理着一个大学项目网络，每年培养600多名高中STEM教师，监督为数百名来自代表性不足群体的年轻人服务的夏季STEM夏令营，并向5000多名高中生教授双招生物理课程。技术总结该奖项支持理论和计算研究，并支持教育，以了解在水力压裂的极端条件下导致材料断裂的物理过程。将美国推上天然气和石油生产国榜首的页岩革命，主要是建立在经验主义发现的基础上的。生产天然气和石油的页岩层具有纳米级的渗透率，这使得似乎不可能生产出经济数量的碳氢化合物。这个问题的解决方案是，水力压裂增产过程创建了裂缝网络，其中裂缝具有足够的密度，使运输成为可能。PI将特别调查三个区域。首先，他将使用岩石和流体耦合的离散元素模型来研究水力压裂过程，并研究流体压力如何导致裂缝网络的形成。其次，他将利用固体电子理论中熟悉的格林函数技术来研究气体向复杂网络的扩散，从而研究网络形状与生产时间历史之间的联系。最后，他将使用流体有限元模型来研究油和水在高度不均匀的地质环境中的流动。为了从这项工作中获得广泛的影响，PI将研究如何通过检查导致最大产量的井的因素来使研究可行，并开发预测油井和气田动态的方法。国际和平研究所还将研究这些发现对向可再生能源过渡的影响。国际和平研究所有许多机会将研究与教育和外联相结合。PI监督一个大学项目网络，该网络每年培养600多名高中STEM教师，监督为数百名来自代表性不足群体的年轻人服务的夏季STEM夏令营，并向5000多名高中生教授双招生物理课程。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

NONTECHNICAL SUMMARYThis award supports theoretical and computational research, and education that brings theoretical materials research to bear on understanding the physical processes that lead to materials fracture under extreme conditions in the context of hydrofracturing and to contribute to understanding the production of gas and oil.The technology called hydrofracturing or fracking has been used for decades, but in its current form it is just over ten years old. The impact of this technological development upon the US has been enormous. The benefit to the US economy in the last 5 years has been well over a trillion dollars, and the US has become the world's largest oil and gas producer.Producing oil and gas from shales appears to be paradoxical. Shales are some of the most impermeable materials known. Nothing should flow through them. So how can they produce revolutionary quantities of gas and oil? The answer is that the hydrofracture process stimulates them, creating networks of cracks, and these cracks must be distributed with fine enough spacing to make production possible.This project will study the physical processes leading to the network of cracks. Part of the study will concern how the cracks form. Part of the study will concern how the network of cracks can be understood using clues from the time history of gas produced at the surface. And part of the study will concern how oil and water flow through very nonuniform rock.To obtain broad impacts from this work, the PI will investigate ways to make the research actionable by examining factors that lead to the most productive wells, and developing methods to predict performance of wells, and gas and oil fields. The PI will also examine the implications of these findings for transitions to renewable energy sources. The PI has numerous opportunities to integrate the research with education and outreach. The PI oversees a network of university programs that prepares over 600 high school STEM teachers a year, oversees summer STEM camps serving hundreds of youth from under-represented groups, and teaches a dual-enrollment physics class to over 5000 high school students.TECHNICAL SUMMARYThis award supports theoretical and computational research, and education to bear on understanding the physical processes that lead to materials fracture under extreme conditions in the context of hydrofracturing. The shale revolution, which has propelled the US to the top of gas and oil-producing countries, was built on largely empirical findings. The shale layers from which gas and oil are produced have nanodarcy permeability, making it seem impossible to produce economical quantities of hydrocarbons. The resolution of this problem is that the hydrofracture stimulation process creates a fracture network where the fractures have sufficient density to make transport possible.The PI will investigate three areas in particular. First, he will use a discrete element model coupling rock and fluid to study the hydrofracture process, and study how fluid pressure leads to the creation of a fracture network. Second, he will make use of Green's function techniques familiar from the electron theory of solids to study the diffusion of gas to complex networks, and thereby examine the connection between shape of the network and the time history of production. Finally, he will use fluid finite element modeling to study the flow of oil and water through highly inhomogeneous geological environments.To obtain broad impacts from this work, the PI will investigate ways to make the research actionable by examining factors that lead to the most productive wells, and developing methods to predict performance of wells and gas and oil fields. The PI will also examine the implications of these findings for transitions to renewable energy sources. The PI has numerous opportunities to integrate the research with education and outreach. The PI oversees a network of university programs that prepares over 600 high school STEM teachers a year, oversees summer STEM camps serving hundreds of youth from under-represented groups, and teaches a dual-enrollment physics class to over 5000 high school students.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.