Gas Flow Behavior of Nanoscale Pores in Shale Gas Reservoirs

• Published in: Energies (Basel) Vol. 10; no. 6; p. 751
• Main Authors: Shen, Weijun, Li, Xizhe, Xu, Yanmei, Sun, Yuping, Huang, Weigang
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.06.2017
• Subjects: Adsorption; Design optimization; flow behavior; Flow velocity; Fractures; Gas flow; Gas production; Gas transport; Gases; Hydraulic fracturing; Hydraulics; Knudsen number; mathematical model; Membrane permeability; nanoscale pores; Navier-Stokes equations; Oil and gas production; Organic matter; Parameters; Permeability; Petroleum engineering; Pores; Porosity; Pressure; Reservoirs; Shale; Shale gas; shale gas reservoirs; Temperature; Thickness; Beijing China; Canada; Netherlands; Calgary Alberta Canada; United States > US; China
• ISSN: 1996-1073; 1996-1073
• DOI: 10.3390/en10060751

Unlike conventional gas reservoirs, shale gas reservoirs are characterized by extremely low porosity, ultra-low permeability and high clay content [3,4]. [...]the pore structures in shale gas reservoirs are varied and heterogeneous, including organic matter, nonorganic matrix, natural fractures and pore space induced by hydraulic fractures [5,6,7]. The giant variation of pores scales makes gas flow in shale gas reservoirs very complex. [...]an understanding of gas flow and transport in shale pores is great significance for gas productivity and for optimizing the hydraulic-fracturing design in shale gas reservoirs. [...]the effects of these parameters on gas flow patterns, such as pressure, temperatures, and adsorption parameters, were also not studied systematically. [...]it is extremely necessary to understand gas flow behavior in shale nanopores and the effects on different flow patterns so as to predict gas production and optimize the fracturing treatment for shale gas reservoirs. For the gas transport in shale nanopores, these flow patterns may exist at the same time, and it is not comprehensive to consider one or two flow process. [...]the total mass flux with multi-flow regimes may be expressed as: J=JV+JS+JT+JM Substituting Equations (5), (9), (14), (18) and (19), we obtain: J=[(1+2+(Kn4.5)41+(Kn4.5)4⋅(1+5Kn))ρgr28μg+1+2(Kn4.5)41+(Kn4.5)42rM3×103RT(8RTπM)0.5]∇p When considering the effect of gas adsorption, the adsorption thickness based on the Langmuir equation can be expressed as: d=d0PP+PL where d is the adsorption thickness; d0 is the max adsorption thickness; and PL is Langmuir pressure.