Influence Factors and Feasibility Evaluation on Geological Sequestration of CO₂ in Coal Seams: A Review

Abstract

The geological sequestration of CO 2 in coal seams holds significant implications for coalbed methane development and greenhouse gas mitigation. This paper examines the principles, influencing factors, and evaluation methods for geological CO 2 sequestration in coal seams by analyzing relevant domestic and international findings. Suitable geological conditions for CO 2 sequestration include burial depths between 300 and 1300 m, permeability greater than 0.01 × 10 −3 μm 2 , caprock and floor strata with water isolation capabilities, and high-rank bituminous coal or anthracite with low ash yield. Geological structures, shallow freshwater layers, and complex hydrological conditions should be avoided. Additionally, the engineering conditions of temperature, pressure, and storage time for CO 2 sequestration should be given special attention. The feasibility evaluation of CO 2 geological storage in coal seams necessitates a comprehensive understanding of coalfield geological factors. By integrating the evaluation principles of site selection feasibility, injection controllability, sequestration security, and development economy, various mathematical models and "one vote veto" power can optimize the sequestration area and provide recommendations for rational CO 2 geological storage layout.

Influence of Depth on CO2/CH4 Sorption Ratio in Deep Coal Seams

“…An increase in the vitrinite reflectance by 0.1% resulted in a reduction of the a mCO2 value by 1.5%. The obtained observations are in contradiction to those obtained by authors dealing with the influence of coal rank on the sorption capacity [13,39], who found that as the vitrinite reflectance increased, the ability of coal to adsorb CO 2 also increased. An explanation for such observations may be the example of studies carried out in relation to CH 4 , which showed a falling and then rising trend [40].…”

“…Some researchers also reported that the CO 2 /CH 4 sorption ratio decreased with the coalification degree increase [13,21]. It was also shown, by examining the CO 2 /CH 4 sorption efficiency, that a higher coalification degree resulted in an increase in the CH 4 displacement rate at low pressures [22].…”

“…The characteristics of coal seam occurrence in terms of burial depth are important indicators for determining the CO 2 sequestration potential [13]. It was determined that the suitable geological conditions for this process include depths from 300 to 1300 m. Laboratory data on the variability of the CO 2 /CH 4 exchange ratio, together with data on the actual depth of the seams, are limited.…”

The geological factors affecting gas content and permeability of coal seam and reservoir characteristics in Wenjiaba block, Guizhou province

“…The burial depth and spatial form of the coal seam refer to the current occurrence state of the coal seam, which is the result of later tectonic movement after the formation of the coal seam 33 . The burial depth of a coal seam affects important reservoir parameters such as coalbed methane content, coal seam permeability, reservoir pressure and reservoir temperature.…”

Three-Dimensional Geological Modeling of Coal Reservoirs and Analysis of Sensitivity Factors for Combined Mining Capacity

“…Monte Carlo simulation has found widespread application in estimating coalbed methane reserves. In this study, we used the Monte Carlo method to simulate values for reservoir parameters and conducted an in-depth analysis of the influence of these parameters on coalbed methane production capacity [25].…”