Non-Darcy Liquid Flow in Shale: Theory and Laboratory Experiment Results
Dr. Hui-Hai Liu
Aramco Research Center, Houston
Spontaneous imbibition of fracturing fluids into a shale formation has many practical applications for shale gas recovery. Because of the strong solid-liquid interaction in low-permeability media, Darcy’s law is not always adequate for describing liquid flow process in a shale formation. This non-Darcy flow behavior (characterized by nonlinearity of the relationship between liquid flux and hydraulic gradient), however, has not been given enough attention in the shale gas community. The current study develops a systematic methodology to address this important issue. We propose a phenomenological model for liquid flow in shale (in which liquid flux is a power function of pressure gradient) and developed an analytical solution to a one-dimensional spontaneous imbibition problem that obeys the model. The validity of our model is verified by satisfactory comparisons of theoretical results and observations from different research groups. Furthermore, based on the developed analytical solution, we also developed a laboratory test methodology using nuclear magnetic resonance imaging to estimate parameters for the phenomenological model from spontaneous imbibition tests. The relative importance of this non-Darcy liquid flow for hydrocarbon production in unconventional reservoirs remains an issue that needs to be further investigated.
About Dr. Hui-Hai Liu
Dr. Hui-Hai Liu is a Petroleum Engineering Consultant with Aramco Research Center (Houston). Before joining Aramco, he had been with Lawrence Berkeley National Laboratory (LBNL) in different scientific and managerial roles for 17 years. He has broad research interests in both petroleum engineering and groundwater hydrology, including theoretical and modeling studies related to flow and transport in fractured rock, coupled hydrological and mechanical processes, physics/properties for multiphase flow, and flow process in low-permeability media. He has published more than 100 peer-reviewed journal articles and one research monograph; his work has been employed as the base case models by several engineering projects of international importance, including the Yucca Mountain Project. He is a fellow of Geological Society of America and recipient of Emil Truog research award from Soil Science Society of America and a Director's award for exceptional achievement from LBNL. He also received several awards from US Department of Energy and its management and operation contractors for his technical leadership. He is currently serving as an associated editor for SPE RE&E journal.