A Systematic Experimental Study of Low Salinity, Carbonated Water and Low Salinity Carbonated Water EOR Injection Schemes in Carbonate Reservoir Conditions

A. A. Alhashboul, A. S. Farzaneh, M. S. Sohrabi

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Smart Water (SW) can be defined as brine that has been chemically adjusted/optimized in terms of salinity and ionic composition or carbonation (CO2 enrichment). The aim is to create a brine with an optimum chemical & ionic composition such that it changes the equilibrium of the oil crude/brine/rock interaction (CBR). Recently, combining more than one EOR method in hybrid mode has gained attention; several SW hybrid modes have been investigated with positive results. The most promising hybrid mode is combining low salinity injection (LSI) with Carbonated Water Injection (CWI). A carbonated Low Salinity Carbonated Water Injection (LSCSWI) study was carried out to both study the effectiveness and explore the prospects of combining carbonated water (phase behaviour), with low salinity (wettability alteration) mechanisms. A series of high-pressure/temperature carbonate reservoir core flood experiments were performed at reservoir conditions (100ºC - 3100 psig), so the incremental oil recovery factor and differential pressure behaviour of Low Salinity (LS), Carbonated Water (CW). LSCW and CO2 EOR injection schemes could be compared. A near perfect oil recovery often associated with miscible CO2 core flooding experiments was achieved. However, field implementations where gravity override challenges of CO2 injection are faced, do not produce oil recovery %'s near the recovery factors that are achieved in miscible CO2 core flooding experiments. The highest incremental oil recovery % IOIP of the waterflooding based injection modes was achieved by tertiary LSCSW, with a value of 28.49%, followed by CSWI at 23.18%, and finally LSSWI at 5.5%. The magnitude effect of the Dp drop caused by the carbonated water's new gas phase that was produced with the effluent was higher than the wettability alteration increases of Dp that was caused by reducing the salinity of the injected brine. Several observations supported the claim that mechanisms of wettability alteration, associated with LSI and phase behavior change associated with CWI, work simultaneously. The wettability alteration mechanism that was triggered by reducing the salinity of injected brine is much more dependent on the remaining oil saturation, in order for it to have a significant positive influence on oil recovery. To the author's best knowledge, there has not been a systematic experimental investigation that compared these four EOR recovery methods, by using the same carbonate reservoir core sample, live crude oil sample and injected brines, at the same reservoir conditions.
Original languageEnglish
Title of host publicationSPE Improved Oil Recovery Conference 2024
PublisherSociety of Petroleum Engineers
ISBN (Print)9781959025245
Publication statusPublished - 22 Apr 2024
EventSPE Improved Oil Recovery Conference 2024 - Tulsa, United States
Duration: 22 Apr 202425 Apr 2024


ConferenceSPE Improved Oil Recovery Conference 2024
Country/TerritoryUnited States


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