Non-isothermal gas flow during carbon sequestration in coalbeds

Abstract

This paper presents a numerical investigation of non-isothermal effects during high pressure carbon dioxide injection in deep coalbeds. Whilst coalbeds provide storage security owing to the large carbon dioxide adsorption capacity of coal, high pressure gas injection may disturb the temperature of the coalbed and influence flow behaviour. A numerical model of coupled heat transfer and gas flow incorporating the Joule-Thomson cooling effect is presented in this paper to study the temperature change induced by carbon dioxide injection. The numerical model is firstly compared with existing results in the literature for verification, and then applied to simulate changes in temperature and pressure of a coalbed during gas flow. Results of predicted temperature and pressure under different injection temperatures show that a zone of cooling occurs when gas injection under the same and low temperature than that of coalbeds, leading to a further drop of pressure in this zone. Although injection under higher temperature can suppress cooling effect, the time for pressure to reach steady state increases.