Work

Dual Control of Permeability-Viscosity in Coalbed CO2 Flow: Carbon Safety Supervision Assessment for Optimized Sequestration

Year: 2025

Type: article

Abstract: High Resolution Image Download MS PowerPoint Slide Geological sequestration of CO 2 in coal seams is one of the effective methods to reduce carbon emissions. However, the combined effects of evolving CO 2 viscosity and the inherently low permeability of coal reservoirs can significantly inhibit CO 2 flow capacity, thereby affecting the overall storage efficiency. The dynamic dual-control mechanisms governing CO 2 migration in coal seams remain insufficiently understood. The analysis of dynamic dual-control weights influencing CO 2 flow behavior is focused on in this study. On this basis, a mathematical model is developed and numerical simulations are conducted. The model captures the transient evolution of CO 2 viscosity and the permeability of coal seams during the sequestration process and investigates the coupling relationship between CO 2 properties and coal seam permeability. Two mathematical decomposition methods─the logarithmic decomposition method and the finite difference decomposition method─are employed to perform parameter decoupling analysis of CO 2 migration in coal seams. The dynamic coupling characteristics between permeability and viscosity are elucidated, and the dominant influence weights of their evolution on the CO 2 flow field are quantitatively evaluated. The study clarifies the stage-dependent control of fluid migration: permeability dominates initially, viscosity gains influence midstage, and both reach dynamic equilibrium over time. A dynamic dual-control weighting approach is proposed to optimize injection strategies, aiming to enhance CO 2 mobility and storage efficiency in an economically viable manner. The findings provide a theoretical basis for the accurate performance assessment of CO 2 sequestration in coal seams.

Source: ACS Omega

DOI: 10.1021/acsomega.5c05268