Mechanisms in CO2-enhanced coalbed methane recovery process

Abstract

Injection of CO 2 and subsequent desorption of CH 4 is considered to be the most efficient enhanced coalbed methane (ECBM) recovery technique to date. Meanwhile, CO 2 -ECBM is an excellent option for CO 2 geo-sequestration for an extended period. Despite ongoing research efforts and several field applications of this technology, the mechanisms of the process have yet to be fully understood. The coalbed heterogeneity, the fluid interactions with coal, the CO 2 induced swelling, and the continuous pressure and composition changes require outright insights for optimal application of the technique. Furthermore, intermolecular interactions of CO 2 and CH 4 , their competitive adsorption on the dry/wet coal surface, and the dispersion and advection processes play an important role in defining the CO 2 -ECBM recovery process. An attempt has been made here to understand the key mechanisms of CO 2 -ECBM recovery in coalfields, particularly the adsorption of CO 2 in the supercritical state at the recommended sequestration depth.

Principle and practice of hydraulic softening top-cutting and pressure relief technology in weakly cemented strata

“…These formations have relatively recent diagenetic ages and certain special properties, such as weak cementation, easy weathering, and ease of becoming muddy and sandy when in contact with water. Consequently, mining operations in these formations face significant challenges (Liu et al, 2020;Liu et al, 2021;Liu et al, 2022;Asif et al, 2022;Liu et al, 2022;Li et al, 2022;Liu et al, 2023). This difficulty necessitates indepth research on utilizing the geological characteristics of western China to implement targeted measures for preserving the weakroof rock layer and regulating the working face weighting (Xu et al, 2018;Wang et al, 2023a;Wang et al, 2023b;Wang et al, 2023c).…”

Development of Empirical and Artificial Neural Network Model for the Prediction of Sorption Time to Assess the Potential of CO2 Sequestration in Coal

“…Geological storage of CO 2 is an emerging field of study and to date, there are no successfully implemented CO 2 -ECBM project in India . Researchers believe that further research is required to understand gas recovery as a result of complex interaction of gases inside the coal matrix and cleats. , To estimate the CO 2 storage potentiality, data measurement becomes a crucial component, whether in conventional or unconventional reservoirs. This requires a considerable budget, particularly for the core analysis.…”

Surrogate-Assisted Evolutionary Optimization of CO2-ESGR and Storage

“…Liu et al summarized the CO 2 -ESGR techniques including CO 2 fracturing technology, CO 2 injection-enhanced gas recovery, and CO 2 geological storage in depleted shale gas reservoirs. The CO 2 -ESGR is similar to CO 2 -enhanced coalbed methane recovery in that CO 2 /CH 4 competitive adsorption is an important mechanism for the displacement of CH 4 . , It is recognized that although the CO 2 injection can effectively accelerate the desorption rate of CH 4 , the actual production process depends largely on various geological and engineering factors, such as porosity, permeability, formation thickness, gas injection volume and time, fracture height, fracture half-length, and fracture conductivity. However, few studies have systematically scrutinized the effect of these engineering and operating parameters on the potential of the CO 2 -ESGR and storage in hydraulically fractured shale gas reservoirs.…”