Program > Keynote Speakers > Xia-Ting Feng

Hydraulic-mechanical coupling problems during the extraction of tight gas at high stresses
Xia-Ting Feng
Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, China; Northeastern University, China
Biosketch

Xia-Ting Feng, BSc, PhD, and graduated and received PhD degree at Northeastern University of Technology (namely Northeastern University since 1992), China in 1992 and then took the position of lecturer, associate professor and professor at the same university. He joined Institute of Rock and Soil Mechanics, the Chinese Academy of Sciences(CAS) in 1998 as a Professor of Hundred Talent Program of the CAS and as Deputy Director in Charge and Director from 2001-2005. He has worked as Director of State Key Laboratory of Geomechanics and Geotechnical Engineering since 2007.He works at Northeastern University, China as a Vice President since September 2017.

Prof. Feng is President of Federation of International Geo-engineering Societies – FedIGS, President of ISRM Commission on Design Methodology, member of ISRM Commission on Testing Methods, and President of Chinese Society for Rock Mechanics and Engineering (CSRME). He was the President of International Society for Rock Mechanics (ISRM) 2011-2015.

He is also Editor-in-Chief of Chinese Journal of Rock Mechanics and Engineering, Associate Editor-in-Chief of Chinese Journal of Theoretical and Applied Mechanics, and Associate Editor-in-Chief of Journal of Rock Mechanics and Geotechnical Engineering. He is members of Editorial Board of International Journal of Rock Mechanics and Mining Sciences (2003-present), Rock Mechanics and Rock Engineering (2010-present), Geomechanics and Tunnelling and (2008-present).

His research interests cover rock mechanics for deep rock engineering. He published more than 170 technical papers and the English book “Rock Engineering Design” and “Rock Engineering Risk” with Professor John Hudson. He has edited five volumes of the book “Rock Mechanics and Rock Engineering” (CRC Press) and the book Rockburst (Elsevier).

http://sourcedb.whrsm.cas.cn/zw/zjrck/200907/t20090720_2114221.html

Abstract

Shale gas is a very important unconventional energy source. Gas is stored in shale mainly in free and adsorbed phases. Since a significant amount of gas in the shale is adsorbed to the organic matter and/or clay minerals, gas adsorption will induce shale swelling, which may then has an impact on the permeability of the gas shale and gas flow behavior in the shale thus its gas production. Nevertheless, laboratory measurement of swelling on shale associated to gas adsorption is very limited due to the long equilibration time and small swelling strain of adsorption-induced shale swelling. Shale gas is occurred in deep-buried reservoir. The pores and matrixes in the shale are compacted by in-situ stress. Therefore, laboratory studies on permeability, gas adsorption and swelling characteristics of shale measured under in-situ stress are needed to understand the stress change in the field conditions. Thus, a coupled, multi-field testing apparatus were developed, which can provide a higher hydrostatic pressure and deviatoric stress environment for permeability, adsorption and swelling experiments. Meanwhile, the experimental methods for accurate measurement of low permeability, small adsorption amount and swelling were established. The kinetic shale swelling and kinetic gas adsorption in different types of gases at various gas pressures under constant confining pressure and temperature were investigated. Permeability of intact gas shale and gas shale with nature fractures under high stress were also been researched. The related results will be shown and discussed in the paper.

Gas shale with very low permeability is tight and hard. In order to obtain commercial production and increase permeability, hydraulic fracturing is the necessary and key technology. Aim to reduce the consumption and pollution in the exploitation of shale gas reservoirs using hydraulic fracturing, a true triaxial apparatus with shale fracture process and permeability evolution testing equipment was developed based on the closed-loop control in loading and multi-field coupling theory and integrated use of the mechanical-electrical-hydraulically controlling technology. The apparatus were consisted of true triaxial cell, thermal control system, gas pressurized fracturing system and permeability tests and data acquisition system. The assessment of mechanical behavior of brittle shale during the fracturing process in true triaxial stress environment, new gas fracturing methods and fracturing gas media selection were investigated.

Modeling fracturing process constitutes another key issue related to tight gas development. We propose an efficient modeling approach called extended embedded discrete fracture model (XEDFM), which is a thermo-hydro-mechanical coupling model. The modeling approach, simulation results, and relevant implication and discussion will be presented in depth.