Impacts of injection temperature on the CO₂ injection capacity in the different sloping formations

The CO₂ injection capacity directly affects the CO₂ storage efficiency. Injection temperature and formation sloping degree affect the CO₂ injection capacity. Based on the actual geological conditions of the Shiqianfeng Formation in the Ordos Basin of China, a three-dimensional (3D) simulation model was established to evaluate pressure, temperature, CO₂ spatial distribution, and injection amount. A total of 17 simulation schemes were carried out using the TOUGH2-ECO2N fluid property module. The results showed that the injection temperature had a significant impact on the CO₂ injection capacity in the different sloping degree formations. Increasing the injection temperature resulted in increased formation pressure, CO₂ gas phase, dissolved phase, and total injection amount, while decreasing the CO₂ concentration, and the formation pressure changed obviously with the formation sloping degree. The larger the formation sloping degree was, the less the CO₂ injection amount. Higher injection temperature and smaller sloping degree formation were more favorable for CO₂ injection, and the CO₂ injection capacity was stronger, signaling that it should be selected to store CO₂ in the future.