Porous characteristics and CO2 storage potential of a thin coal seam in the northwest Huangling mining area
To study the storage potential and main controlling factors of CO2 in thin coal seams,a thin coal seam in the northwest of the Huangling mining area in the Shaanxi Province was taken as an exam-ple,and such experimental methods as mercury intrusion,liquid nitrogen,nuclear magnetic resonance,and CO2 isothermal adsorption were applied to explore the characteristics of pore fracture system and permeability of coal reservoir under the controls of macroscopic coal rock types,and to reveal the differ-ence of CO2 adsorption capacity in different water-bearing states and its internal reasons.The results show that the vitrinite content of semi-bright coal sample is high,and the pore and fracture systems at all levels are developed and well connected;The content of inertinite and minerals in semi-dark coal sample is high,and the pores are mainly micro-pores,with poor pore connectivity;The porosity and per-meability conditions of semi-bright coal sample are better than those of semi-dark coal sample,provi-ding convenient conditions for CO2 injection.The coal seam has a strong CO2 adsorption capacity.Un-der dry conditions,the CO2 adsorption capacity of semi-bright coal sample is greater than that of semi-dark coal sample,while under equilibrium water conditions,the adsorption capacity relationship is re-versed,which is due to the wettability difference under the controls of macroscopic coal rock types.Semi-bright coal sample with stronger wettability has higher water content under the conditions of equi-librium water state,which will reduce CO2 adsorption space and block roaring channels,thereby reduc-ing its CO2 adsorption capacity.The conclusions indicate that:CO2 storage sites under thin coal seam conditions should prioritize adsorption and storage advantage areas with high bright component content and low moisture content to compensate;The coal rock composition(type)and moisture content of coal will be important basic parameters for evaluating the potential of CO2 storage in thin coal seams.
CO2 storagethin coal seamadsorptionpore and fracturemacroscopic coal rock type
国家科技期刊平台
NSTL
万方数据
