Extraction and numerical simulation of gas–water flow in low permeability coal reservoirs based on a pore network model.
- Resource Type
- Article
- Authors
- Han, Ya-Feng; Cheng, Xiao-Yang; Liu, Xin-Rong; Zhao, Lei-Lei; He, Jun; Miao, Jie
- Source
- Energy Sources Part A: Recovery, Utilization & Environmental Effects. 2021, Vol. 43 Issue 16, p1945-1957. 13p.
- Subject
- *FLOW simulations
*PERMEABILITY
*IMAGE processing software
*COAL
*COMPUTER simulation
*SOIL permeability
- Language
- ISSN
- 1556-7036
This study aimed to investigate the effects of pore structure on gas–water permeability in low permeability coal reservoirs. A 3D digital coal model with macropores (>13.85 μm) was constructed by using a μCT225kVFCB test system and Avizo image processing software. An equivalent pore network model (EPNM) was extracted on the basis of the 3D model. PoreFlow was used to simulate the micro-flow process of gas and water in the EPNM. A control variable method was used to analyze the influence of pore structure on relative permeability. Results showed a sensitive zone in the relative permeability of the non-wetting phase in the low permeability coal reservoir. In this zone, the relative permeability of the gas phase showed remarkable variations, and the changes of the pore throat ratio (PTR) were minimal. In addition, a critical throat radius (TR) was established in the low permeability coal reservoir with water saturation (Sw) of less than 48.33%. Gas fluidity was poor when TR reached its critical value. The water phase relative permeability (Krw) increased with the increase of PTR. The variation of Krw was minimal as the coordination number (CN) increased. The influence of the pore throat structure on Krw was ranked as PTR>TR>CN. [ABSTRACT FROM AUTHOR]