Cyclic pumping technique to increase CO2 sequestration in fractured geothermal reservoirs

Abstract

Carbon dioxide (CO2) sequestration in deep geothermal reservoirs is one of the promising technique to reduce global temperature by decreasing the atmospheric CO2 content. In this study, a cyclic pumping technique is proposed and applied in an enhanced geothermal system (EGS) for CO2 sequestration together with heat mining process. Cyclic pumping at higher frequency (small interval of days) can significantly increase the accumulated amount of CO2 sequestrated. Reducing the pumping frequency results to lower amounts of CO2 sequestrated, less than using a fixed pumping pressure. The pumping frequency refers to the number of days between maximum to minimum pressure interchange. Furthermore, compared to a fixed low pumping pressure, a cyclic pumping technique improves geothermal heat extraction ratio, thus higher performance of the EGS.