Shale gas and oil have dramatically changed the hydrocarbon production landscape in recent years, e.g., the contribution of shale gas to dry natural gas production in the U.S. has grown from <1% in 2005 to nearly 50% today. Effective prediction of gas/oil production rate and management of waste fluids (e.g., fracking fluids) are essential for the success of shale gas/oil extraction operations. Because the porosity in shales is dominated by pores smaller than 10-100nm, confinement and chemistry of pore walls can significantly affect the storage and transport of gas and oils in shales, and their effects are underpinned by physical processes at the molecular scale. In this talk, I will introduce our work on the molecular thermodynamics and hydrodynamics of shale gas and oil recovery. I will first examine the storage and recovery of shale gas at the single-pore scale, focusing on the mode of gas storage, the scaling law of gas recovery, and the effects of multiple gas components on gas production. Next, I will examine surface hydration, a new form of water imbibition when capillary flow into a gas-filled nanopore is suppressed. Finally, I will present studies on the invasion of gas bubbles and oil droplets into water-filled nanopores and highlight the importance of disjoining pressure in determining the thermodynamics of gas and droplet invasion.
Dr. Rui Qiao received his B.S. degree from Huazhong University of Science and Technology and an M.S. degree from Tsinghua University. He obtained his Ph.D. and postdoctoral training at the University of Illinois at Urbana-Champaign. He was a faculty at Clemson University from 2005 to 2014 and joined Virginia Tech in 2014. He has worked on the molecular, continuum, and multiscale simulations of diverse problems including nanofluidics, mass and heat transfer in porous media, shale gas extraction, and electrical energy storage. These works share the theme of clarifying the essential physics of interfacial and transport phenomena underlying advanced technologies to shape and accelerate their development.