Nanofluidics Foundation for Shale Gas Recovery

该项目的目的是研究页岩地层的天然气采收率和压裂流体运移。页岩中的天然气是一种丰富的能源资源。在水力压裂等生产技术的推动下，近年来页岩气的蓬勃发展改变了美国的天然气市场。然而，页岩气的生产面临着许多挑战：天然气采收率的迅速下降，以及页岩地层中水力压裂液（“压裂液”）的管理困难，往往阻碍了有利可图的生产。在这个项目中，通过在纳米孔尺度上发展对页岩地层中天然气和压裂流体输送的基本理解，解决了这些挑战。在这里获得的见解将有助于改善页岩气的生产和压裂液的管理，从而使页岩气行业和社会都受益。研究生和本科生将接受跨学科研究的培训，包括流体动力学、界面化学和计算工程。编制总结页岩气田孔隙尺度研究最新进展的通讯，发送给行业内的模拟从业者。将创建和维护一个YouTube频道，以帮助提高公众对化学在流体动力学中的作用的认识。页岩气的开采最终是由纳米孔隙水平上的天然气和压裂流体输运控制的，在纳米孔隙水平上对页岩气开采进行可靠的模拟必须建立在对纳米孔隙水平上输运的充分理解的基础上。在本项目中，将使用分子模拟和连续介质模拟来研究纳米孔中单组分和多组分气体的采收率以及压裂液进入纳米孔的渗吸作用。在孔隙水平上对天然气采收率的研究将阐明约束和气壁相互作用对天然气采收率的协同作用。在孔隙尺度上研究压裂液的运移，将阐明压裂液的溶液化学性质以及纳米孔的大小、表面化学性质和局部饱和度对压裂液吸吸和气体运移的影响。这些研究将有助于进一步推进页岩气采收率和压裂流体运移的建模和模拟。其中，气采研究将为半现象学孔隙尺度气采模型的选择和参数化提供理论依据和指导；多相输运研究将为页岩地层多相输运模拟研究开辟新天地，突破目前主要基于经典毛细管流动的主流框架。

The objective of this project is to investigate the gas recovery and fracking fluid migration in shale formations. Natural gas trapped in shale formations is an abundant energy resource. Enabled by production technologies such as hydraulic fracturing, the recent shale gas boom has transformed the natural gas market in the U.S. Nevertheless, shale gas production faces many challenges: profitable production is often hindered by the rapid decline of the gas recovery rate and the difficulties in managing the hydraulic fracturing fluids ("fracking fluids") in shale formations. In this project, these challenges are addressed by developing a fundamental understanding of the transport of gas and fracking fluids in shale formations at the nanopore scale. The insights gained here will help improve the production of shale gas and management of fracking fluids, thereby benefiting both the shale gas industry and the society. Graduate and undergraduate students will be trained in interdisciplinary research covering fluid dynamics, interfacial chemistry, and computational engineering. Newsletters summarizing recent pore-scale research in the shale gas field will be compiled and sent to simulation practitioners in the industry. A YouTube channel will be created and maintained to help increase the awareness of the role of chemistry in fluid dynamics by the public.Shale gas recovery is ultimately controlled by gas and fracking fluid transport at the nanopore level and reliable simulation of shale gas recovery at field-scale must be built upon sound understanding of transport at the nanopore scale. In this project, the recovery of single- and multi-component gas from nanopores and the imbibition of fracking fluids into nanopores will be studied using molecular and continuum simulations. The study of gas recovery at the pore level will elucidate the synergistic effects of confinement and gas-wall interactions on the gas recovery. The study of fracking fluid transport at the pore scale will clarify how fracking fluid imbibition and gas transport are affected by the solution chemistry of fracking fluids as well as the size, surface chemistry, and partial saturation of nanopores. These studies will help further advance the modeling and simulation of gas recovery and fracking fluid migration in shale formations. In particular, the gas recovery study will provide theoretical basis and guidelines for selecting and parameterizing semi-phenomenological pore-scale gas recovery models; the multiphase transport study will break new ground for research on the simulation of multiphase transport in shale formations to move beyond the prevailing framework, which is based mostly on the classical capillary flows.