Reza Rahimi - Undergraduate petroleum engineering student
Ali Taheri - Undergraduate petroleum engineering student

CO۲ enhanced gas recovery (CO۲-EGR) is a promising technology to extract additional natural gas from depleted reservoirs with storing CO۲ into underground formations. This work conducted CO۲-EGR simulations in a heterogeneous gas reservoir by using isothermal and non-isothermal models and systematically analyzed the effects of various CO۲ injection parameters on natural gas recovery, CO۲ storage, and their comprehensive benefits. The results indicate that the CO۲ injection well should be perforated in the lower position, whose overlaid layers with low permeability hinder the upward migration of CO۲, and the larger natural gas recovery and CO۲ storage can be achieved simultaneously for better comprehensive benefits. The optimal injection rate is ۱۳۷.۲۹ m۳·d−۱ to achieve the highest recovery factor of ۶۴.۸۷%. The decrease in injection temperature and the increase in injection pressure are averse to the enhancement of recovery but beneficial to larger CO۲ storage. The comprehensive benefits of natural gas recovery and CO۲ storage are insensitive to the change of injection pressure and temperature, despite that every single one of them is more subjective to injection pressure than temperature. It's hoped that the findings of this work provide some theoretical guidance for the application of CO۲-EGR.

CO۲-EGR, EGR, CCS