ararefaction coefficient, dimensionlessbslip factor, dimensionless$B_{\mathrm{g}}$gas volume factor, dimensionless$B_{\mathrm{w}}$water volume factor, dimensionless$C$stress sensitivity coefficient (compressibility coefficient), MPa⁻¹$D$vertical depth of the fluid, m$D_{\mathrm{c},0}$initial pore diameter, m$D_{\mathrm{c}}$effective pore diameter, mggravitational acceleration, 9.8 m/s²$h$thickness of the grid block, m$i,j,k$are coordinates of the grid block, dimensionless$k_a$absolute permeability, m²$K_B$Boltzmann constant, J·K⁻¹$k_{\mathrm{c}}$absolute permeability of inorganic matrix, m²$k_{\mathrm{crg}}$relative permeability of gas in inorganic matrix, dimensionless$k_{\mathrm{crw}}$relative permeability of water in inorganic matrix, dimensionless$k_{\mathrm{hfrg}}$relative permeability of gas in hydraulic fractures, dimensionless$k_{\mathrm{hfrw}}$relative permeability of water in hydraulic fractures, dimensionless$k_{\mathrm{hfr}l}$relative permeability of l phase (either gas or water) in the fracture system$k_{\mathrm{mfrg}}$relative permeability of gas in microfractures, dimensionless$k_{\mathrm{mfrw}}$relative permeability of water in microfractures, dimensionless$k_{\mathrm{mf}0}$initial permeability of microfractures, m²$Kn$Knudsen number, dimensionless$k_{\mathrm{o}}$absolute permeability of organic matrix, m²$k_{\mathrm{s},\mathrm{mf}}$permeability of microfractures considering stress sensitivity, m²$k_{\mathrm{s},\mathrm{hf}}$permeability of hydraulic fractures considering stress sensitivity, m²$L$length of a single inorganic nanochannel, mnnormal vector, dimensionless$p_{\mathrm{c}}$capillary pressure, MPa$p_{\mathrm{cc}}$capillary pressure in inorganic matrix, MPa$p_{\mathrm{cg}}$pressure of gas in inorganic matrix, MPa$p_{\mathrm{cw}}$pressure of water in inorganic matrix, MPa$p_{\mathrm{cg}}^0$initial gas pressure in inorganic matrix, MPa$p_{\mathrm{e}}$displacement pressure, MPa$p_{\mathrm{hfc}}$capillary pressure in hydraulic fractures, MPa$p_{\mathrm{hfg}}$pressure of gas in hydraulic fractures, MPa$p_{\mathrm{hfw}}$pressure of water in hydraulic fractures, MPa$p_{\mathrm{hfg}}^0$initial gas pressure in hydraulic fractures, MPa$p_{\mathrm{Lo}}$Langmuir pressure of organic matrix, MPa$p_{\mathrm{Lc}}$Langmuir pressure of inorganic matrix, MPa$p_{\mathrm{mfc}}$capillary pressure in microfractures, MPa$p_{\mathrm{mfg}}$pressure of gas in microfractures, MPa$p_{\mathrm{mfw}}$pressure of water in microfractures, MPa$p_{\mathrm{mfg}}^0$initial gas pressure in microfractures, MPa$p_{\mathrm{mf}0}$initial pressure in microfractures, MPa$p_{\mathrm{og}}$gas pressure in organic matrix, MPa$p_{\mathrm{og}}^0$initial gas pressure in organic matrix, MPa$p_{\mathrm{wf}}$bottomhole flowing pressure, MPa$q_{\mathrm{c}–\mathrm{mf},\mathrm{g}}$gas exchange term from inorganic matrix to microfractures, sm³/m³/s$q_{\mathrm{c}-\mathrm{mf},\mathrm{w}}$water exchange term from inorganic matrix to microfractures, sm³/m³/s$q_{\mathrm{g}}$volume of gas produced per unit volume of shale, sm³/m³/s$q_{\mathrm{mf}-\mathrm{hf},\mathrm{g}}$gas exchange term from microfractures to hydraulic fractures, sm³/m³/s$q_{\mathrm{mf}-\mathrm{hf},\mathrm{w}}$water exchange term from microfractures to hydraulic fractures, sm³/m³/s$q_{\mathrm{o}-\mathrm{c},\mathrm{g}}$gas exchange term from organic matrix to inorganic matrix, sm³/m³/s$q_{\mathrm{w}}$volume of water produced per unit volume of shale, sm³/m³/s$r_{\mathrm{e}}$equivalent radius of the grid block at the well location, m$r_n$throat radius of the nanopores, m$r_{\mathrm{w}}$radius of the wellbore, m$S$skin factor, dimensionless$s_{\mathrm{cg}}$saturation of gas in inorganic matrix, dimensionless$s_{\mathrm{cw}}$saturation of water in inorganic matrix, dimensionless$s_{\mathrm{cw}}^0$initial saturation of water in inorganic matrix, dimensionless$s_{\mathrm{ew}}$normalized water saturation, dimensionless$s_{\mathrm{hfg}}$saturation of gas in hydraulic fractures, dimensionless$s_{\mathrm{hfw}}$saturation of water in hydraulic fractures, dimensionless$s_{\mathrm{hfw}}^0$initial saturation of water in hydraulic fractures, dimensionless$s_{\mathrm{mfg}}$saturation of gas in microfractures, dimensionless$s_{\mathrm{mfw}}$saturation of water in microfractures, dimensionless$s_{\mathrm{mfw}}^0$initial saturation of water in microfractures, dimensionless$s_{\mathrm{og}}$gas saturation in organic matrix, dimensionless$s_{\mathrm{wc}}$irreducible water saturation, dimensionless$V_{\mathrm{Lo}}$Langmuir volume of organic matrix, m³/kg$V_{\mathrm{Lc}}$Langmuir volume of inorganic matrix, m³/kg$\nabla$Hamilton operator, dimensionless$\alpha$shape factor, 1/m²${\varphi }_{\mathrm{c}}$porosity of inorganic matrix, dimensionless${\varphi }_{\mathrm{mf}0}$initial porosity of microfractures, dimensionless${\varphi }_{\mathrm{o}}$porosity of organic matrix, dimensionless${\varphi }_{\mathrm{s},\mathrm{hf}}$porosity of hydraulic fractures considering stress sensitivity, dimensionless${\varphi }_{\mathrm{s},\mathrm{mf}}$porosity of microfractures considering stress sensitivity, dimensionless$\lambda$distribution index of pore size, dimensionless${\lambda }_{\mathrm{g}}$half-transmissibility of gas, m²/Pa/s${\lambda }_{\mathrm{w}}$half-transmissibility of water, m²/Pa/s${\mu }_g$viscosity of gas, MPa·s${\mu }_{\mathrm{w}}$viscosity of water, MPa·s${\rho }_{\mathrm{bi}}$density of shale rock, kg/m³${\rho }_{\mathrm{cg}}$density of gas in inorganic matrix, kg/m³${\rho }_{\mathrm{cw}}$density of water in inorganic matrix, kg/m³${\rho }_{\mathrm{hfg}}$density of gas in hydraulic fractures, kg/m³${\rho }_{\mathrm{hfw}}$density of water in hydraulic fractures, kg/m³${\rho }_{\mathrm{mfg}}$density of gas in microfractures, kg/m³${\rho }_{\mathrm{mfw}}$density of water in microfractures, kg/m³${\rho }_{\mathrm{og}}$density of gas in organic matrix, kg/m³$\delta$effective collision diameter of gas molecules, m$\delta (i,j,k)$Dirac function, dimensionless$\xi$permeability correction factor, dimensionless${\xi }_{\mathrm{c}}$permeability correction factor of inorganic matrix, dimensionless${\xi }_{\mathrm{o}}$permeability correction factor of organic matrix, dimensionless