Analysis of main influence factors of wellbore temperature and pressure fields in injecting CO_2 process

In the process of injecting CO 2,the wellbore temperature and pressure fields are influenced by injection gas parameters, wellbore structure and so on,which directly related to the development effect of injection gas. The wellbore temperature and pressure distribution models are established by studying on heat transfer mechanism between low temperature CO 2 and wellbore,reservoir,in which the variation of fluid phase state and thermophysical properties are comprehensively considered. They are solved using four-order Runge- Kutta method,and the corresponding numerical simulation software for wellbore temperature and pressure fields is developed. The study on the wellbore temperature and pressure varying laws in injecting CO 2 process shows that: gas injection rate,cumulative gas injection amount and casing diameter have great influence on bottom-hole temperature,and injection gas temperature has great influence on bottom-hole pressure.