Investigation of oil recovery and CO2 storage during secondary and tertiary injection of carbonated water in an Iranian carbonate oil reservoir

Effects of geochemistry and interphase transport of CO2on hybrid carbonated low salinity waterflood to improve oil recovery and CO2sequestration

“…During CO 2 injection, the CO 2 dissolves in the oil, reducing oil viscosity and swelling oil . In addition to the EOR potential, it potentially sequestrates the greenhouse gas of CO 2 in depleted reservoirs . This promising CO 2 injection has some disadvantages.…”

“…Because CO 2 gas has low viscosity and density, CO 2 gas injection might cause an unfavorable sweep efficiency and early breakthrough of CO 2 . Besides, there is a high risk of CO 2 gas leakage due to the fact that CO 2 is free and highly mobile in reservoirs during CO 2 gas injection . To overcome the challenging problems, various designs of CO 2 EOR have been developed such as water‐alternating‐gas (WAG), simultaneous water and gas (SWAG), and carbonated waterflood (CWF) …”

“…Although WAG and SWAG processes improve sweep efficiency, they could have inherent adverse effects such as high water saturation and water shielding in water‐flooded reservoirs. The existence of a water barrier due to the adverse effects mitigates the CO 2 mass transfer into the oil phase, resulting in less oil viscosity reduction and swelling . In addition, the time scale for CO 2 diffusion in the oil can be longer due to the low sweep efficiency and gravity segregation during WAG and SWAG processes .…”

“…From commercial application of CWF deployed in Oklahoma, Texas, and Kansas in 1958, considerable improvements in oil recovery and injectivity were monitored. Recently, experimental works and numerical simulation have demonstrated the potential of CWF to enhance oil recovery and CO 2 storage . Seyyedi and Sohrabi observed oil swelling, oil viscosity reduction, mineral dissolution, and contact angle change contributing to the oil production.…”

Laboratory investigation of oil viscosity effect during carbonated water injection: Comparison of secondary and tertiary recovery

“…In comparison with CO 2 injection, CWI needs a smaller amount of gas, improves mobility and sweep efficiency, reduces the gravity segregation and fingering, and consequently leads to higher oil recovery. [12][13][14][15][16][17][18][19][20][21] The main mechanisms of oil recovery in CWI, as a result of transferring CO 2 from the aqueous phase to the oil phase, are oil swelling and viscosity reduction. CO 2 solubility in water at reservoir pressure and temperature is nearly 30 m 3 /m 3 (168.62 SCF/bbl), which is higher than that for any hydrocarbon gases and is appropriate for both oil recovery and a storage plan.…”