Study on the effect of acidification reaction conditions on the pore structure of coal samples based on 2D NMR T1-T2

Abstract

Acidification is one of the commonly used techniques to improve the efficiency of mine dust control. In order to study the effect of acidification conditions on the pore structure of the reservoir, coal acidification experiments were carried out at different temperatures and pressures, and the pore structure was quantitatively characterized by combining with NMR technology. The results showed that the porosity of coal samples increased from 5.8465% to 10.3502%; the signal peak intensity of 2D spectrum increased from 8.72 to 44.8; φ_N and φ_NF of coal samples were positively proportional to the acidification conditions, while D_T and D_F were inversely proportional to the temperature and pressure conditions. Therefore, increasing the acidification temperature and pressure conditions can effectively expand the pore space of coal and enhance the connectivity between pores. By changing the physical–chemical structure of the coal seam through acidification, the purpose of dust control at source can be achieved.