Lattice Boltzmann Model for Gas Flow through Tight Porous Media with Multiple Mechanisms

Area of Science:

• Petroleum Engineering
• Computational Fluid Dynamics
• Geophysics

Background:

• Tight gas reservoirs present complex underground gas flow dynamics.
• Simultaneous modeling of gas slippage and stress sensitivity in porous media is challenging.
• Existing models often fail to capture these coupled effects accurately.

Purpose of the Study:

• To develop and validate a lattice Boltzmann model for simulating gas flow in porous media.
• To incorporate gas slippage and stress sensitivity of permeability and porosity into the model.
• To investigate the impact of these mechanisms on gas flow dynamics and reservoir performance.

Main Methods:

• Development of a lattice Boltzmann model incorporating gas slippage and stress sensitivity.
• Calculation of apparent permeability and porosity based on intrinsic properties and pressure.
• Simulation of gas flow in 2D homogeneous porous media, porous media with varying mineralogy, and fractured porous media.

Main Results:

• Gas slippage was found to enhance flow rate in tight porous media.
• Stress sensitivity of permeability and porosity was shown to reduce flow rate.
• Fractures aligned with the pressure gradient significantly increased flow rate, while perpendicular fractures had minimal impact.
• Gas slippage dominated permeability under low pressure in unfractured media, while stress sensitivity was more critical in fractured media.

Conclusions:

• The developed lattice Boltzmann model effectively simulates gas flow with coupled slippage and stress sensitivity effects.
• Gas slippage and stress sensitivity significantly influence gas flow behavior and reservoir performance.
• Fracture orientation critically affects flow enhancement, with implications for reservoir development strategies.