Carbonated Smart Water Injection for Optimized Oil Recovery in Chalk at High Temperature

Finding cost-efficient ways of increasing oil production with a low carbon footprint is the new challenge for petroleum industry that wants to meet net-zero emission goals by 2050. Smart water injection an EOR process increases and delays breakthrough wettability alteration. Seawater smart in chalk reservoirs, being especially effective at high temperatures. Different studies have shown effectiveness seawater can be further improved modifying ion composition before injection. Carbonated (CW) has been proposed as potential fluid. In addition producing extra oil, reduction greenhouse gas (CO 2 ) atmosphere achieved using carbonated The main mechanism behind increased recovery injecting believed viscosity swelling, CO transferred from aqueous phase phase. Wettability alteration also possible mechanism, this hypothesis investigated study along other mechanisms. Stevns Klint outcrop was used study, material recognized excellent analogue North Sea reservoirs. Optimized temperature (130°C) flooding formation (CFW) (CSW), compared saline (FW) (SW) flooding. oil/brine/rock/CO interactions were tracked measuring pH produced (PW) identifying any mineralogical changes SEM (Scanning Electron Microscope) EDX (Energy Dispersive X-Ray) analyses. solubility different brines measured simulation data performed PHREEQC. diffusion analysed check if enough diffused into By CSW both secondary tertiary modes, slight increase observed found best performing brine. slightly CFW mode after FW which does not behave like carbonates. pressure decreasing brine salinity. acidity CW did pressure. No pore surface minerals flooding, confirming limited mineral dissolution. A mass transfer confirmed experimental work, but significant amount remained most likely linked swelling or dissolution could affect porosity permeability rock system. more explanation needs looked confirmation.