Enhanced oil recovery (EOR) methods are mostly based on different phenomena taking place at the interfaces between fluid-fluid and rock-fluid phases. Over the last decade

carbonated water injection (CWI) has been considered as one of the multi-objective EOR techniques to store CO

2

in the hydrocarbon bearing formations as well as improving oil recovery efficiency. During CWI process

as the reservoir pressure declines

the dissolved CO

2

in the oil phase evolves and gas nucleation phenomenon would occur. As a result

it can lead to oil saturation restoration and subsequently

oil displacement due to the hysteresis effect. At this condition

CO

2

would act as insitu dissolved gas into the oil phase

and play the role of an artificial solution gas drive (SGD).In this study

the effect of SGD as an extra oil recovery mechanism after secondary and tertiary CWI (SCWI-TCWI) modes has been experimentally investigated in carbonate rocks using coreflood tests. The depressurization tests resulted in more than 25% and 18% of original oil in place (OOIP) because of the SGD after SCWI and TCWI tests

respectively. From the ultimate enhanced oil rec

overy point of view

the efficiency of SGD was observed to be more than one-third of that of CWI itself. Furthermore

the pressure drop data revealed that the system pressure depends more on the oil production pattern than water production.