The Effect of Lithology on EOR and CO2 Geo-Storage Potentials of Carbonated Water Flooding

Numerous experimental studies on carbonated water flooding (CWF) in micromodels, sand-packs, and sandstone rocks can be found in the literature, yet direct information and measured data on oil recovery by CWF from carbonate rocks is very limited. Additionally, instead of using real reservoir crude and selecting operational conditions of actual reservoirs, several studies have utilized refined oil and opted for non-realistic operational conditions which can bring about results that are not applicable to actual field cases. Furthermore, nearly all publications on CWF are predominantly focused on the oil recovery aspect of this process and concentrate less on its potential to safely store large amounts of CO2 in geological reservoirs.

In this work, core flooding experiments were conducted to assess the EOR and CO2 storage potential of CWF in an oil field. To address the issues raised above, the following measures were taken: (i) core samples of two different types of lithology, i.e., carbonate and sandstone, were selected; (ii) the indigenous pressure and temperature condition of a reservoir was taken as test condition; (iii) the oil samples used in the study were collected from the oil field under investigation; (iv) CWF was investigated as a coupled method of EOR and CCUS.