Influences of burial depth on pore structure of high-rank coal during the CO₂ storage process

CO₂ storage into deep high rank coal has the positive effect on enhancing the CH₄ recovery and sealing the CO₂. The samples before and after the CO₂ storage simulation experiments were analyzed by Mercury porosemitry and low temperature liquid adsorption, the pore structure evolution characteristics of CO₂ storage in different burial depth was discussed. The results show that the true density, bulk density, pore volume, coal matrix volume changes, swelling and contraction of coal are all suffering from different evolution features. The influence of depth on geochemical reaction is not a linear relationship. A maximum depth that has significant influences on micropores and specific area exists. This burial depth is best for the reconstruction of pore systems in coal and more favorable for CH₄ recovery and CO₂ geological storage.