Experimental studies of CO2-brine-rock interaction effects on permeability alteration during CO2-EOR

Abstract

Carbon dioxide (CO2) sequestration through CO2 enhanced oil recovery (EOR) in oil reservoirs is one way to reduce this gas in the atmosphere. Undesirable chemical reactions that occur during these operations can affect the reservoir structure and characteristics. In this study, the effect of CO2-water-rock interaction on the rock permeability alteration and final oil recovery has been evaluated experimentally during CO2 injection into a carbonate rock. The effect of flow rate, displacement type and pressure were investigated during CO2 EOR injection. Different scenarios of miscible/immiscible displacement, secondary/tertiary recovery has been evaluated for different levels of connate water salinity and injection rate. The results show that the severity of damage is directly related to the injection rate, however change in displacement type from miscible to immiscible reduce the intensity of chemical reactions in porous medium. Moreover, in the tertiary CO2 injection, the chemical reactions become more severe due to the higher water saturations. Interestingly, this growth in the level of chemical reactions has a negligible impact on permeability reduction, since the major volume of possible reactions occurs in coarse and high permeable pores. Results reveal that damage is more intense in the case of more saline water.

Geochemical Integrity of Wellbore Cements during Geological Hydrogen Storage

“…It is worth noting that it is possible that chloride ions from the dissolved salts accelerate a hydration reaction mechanism leading to a reduction in the contact area between cement grains and water, and therefore, chemical reactions are less likely to occur in this system. 26,27 Overall, this study showed that hydrogen does not react significantly with the three investigated wellbore cements. It therefore suggests a negligible impact of hydrogen on the integrity of the wellbore cements during geological hydrogen storage operations in salt caverns and porous rock reservoirs.…”

“…Accordingly, the high salinity of 250 ppt does not affect the chemical reaction in the cement/hydrogen/brine system. It is worth noting that it is possible that chloride ions from the dissolved salts accelerate a hydration reaction mechanism leading to a reduction in the contact area between cement grains and water, and therefore, chemical reactions are less likely to occur in this system. , …”

Impact of Hydrodynamic and Interfacial Interactions on Scale Formation in a Capillary Microchannel

“…The deposition process is closely associated with the various aspects of interactions between scale, brine, and the rock surface. − As illustrated in Figure , these interactions could be categorized into geochemical and interfacial forms. The geochemical interactions are based on the potential chemical reactions between the ionic species present in brines and during the interaction with rock surfaces at an equilibrium state.…”