Geochemical Modeling of Hybrid Surfactant and Engineered Water Injections in Carbonate Reservoirs under Harsh Conditions

Engineered water injection (EWI) has gained popularity as an effective technique for enhancing oil recovery. Surfactant flooding is also a well-established and commercially-available technique in the petroleum industry. In this study, a numerical simulation model is developed and used to investigate the hybrid effect of surfactant-EWI in carbonates. This developed model was validated by history-matching a recently conducted surfactant coreflood in the secondary mode of injection. Oil recovery, pressure drop, and surfactant concentration data were utilized. The surfactant flooding model was then coupled with a geochemical model that captures different reactions during engineered water injection. The geochemical reactions considered include: aqueous, dissolution/precipitation, and ion- exchange reactions. Also, different simulation scenarios were considered including waterflooding, surfactant flooding, engineered water injection, and the hybrid surfactant-EWI technique. For the case of EWI, wettability alteration was considered as the main mechanism underlying incremental oil recovery. However, both wettability alteration and interfacial tension reduction mechanisms were considered for surfactant flooding depending on the type of surfactant used. The results showed that for the hybrid surfactant-EWI, wettability alteration is considered as the controlling mechanism where surfactant boosts oil recovery rate through increasing oil relative permeability while EWI reduces residual oil. Moreover, the simulation runs showed that the hybrid surfactant-EWI is a promising technique for enhancing oil recovery from carbonates under harsh conditions. The hybrid surfactant-EWI outperformed other injection techniques followed by EWI, then surfactant flooding, and least waterflooding. This work gives more insight into the application of hybrid surfactant-EWI on enhancing oil recovery from carbonates.

Geochemical Modeling of Hybrid Surfactant and Engineered Water Injections in Carbonate Reservoirs under Harsh Conditions

Summary Engineered water injection (EWI) has gained popularity as an effective technique for enhancing oil recovery. Surfactant flooding is also a well-established chemical enhanced-oil-recovery (EOR) technique in the petroleum industry. The hybrid surfactant flooding/EWI (surfactant/EWI) technique has been studied experimentally and showed promising results. However, there are very limited numerical applications on the hybrid surfactant/EWI technique in carbonates in the literature. Also, the studies applied under harsh conditions of high temperature and high salinity are even fewer. In this study, a numerical-simulation model is developed and used to investigate the hybrid effect of surfactant/EWI in carbonates under harsh conditions. This developed model was validated by history matching a recently conducted surfactant coreflood in the secondary mode of injection. Oil recovery, pressure drop, and surfactant-concentration data were used. The surfactant-flooding model was then coupled with a geochemical model that captures different reactions involved during EWI. The geochemical reactions considered include aqueous, dissolution/precipitation, and ion-exchange reactions. The proposed model has been further validated by history matching another experimental data set. Furthermore, different simulation scenarios were considered, including waterflooding, surfactant flooding, EWI, and the hybrid surfactant/EWI technique. For the case of EWI, wettability alteration was considered as the main mechanism underlying incremental oil recovery. However, both wettability alteration and interfacial-tension (IFT) reduction mechanisms were considered for surfactant flooding depending on the type of surfactant used. The results showed that for the hybrid surfactant/EWI, wettability alteration is considered as the controlling mechanism where surfactant boosts oil-recovery rate through increasing oil relative permeability while EWI reduces residual oil. Moreover, the simulation runs showed that the hybrid surfactant/EWI is a promising technique for enhancing oil recovery from carbonates under harsh conditions. Also, hybrid surfactant/EWI results in a more water-wetting rock condition compared with that of EWI alone, which leads to lower injectivity, and hence, lower rate of propagation for ion-concentration waves. The hybrid surfactant/EWI outperformed other injection techniques followed by EWI, then surfactant flooding, and finally waterflooding. This work gives more insight into the application of hybrid surfactant/EWI on enhancing oil recovery from carbonates. The novelty is further highlighted through applying the hybrid surfactant/EWI technique under harsh conditions. In addition, the findings of this study can help in better understanding the mechanism behind enhancing oil recovery using the hybrid surfactant/EWI technique and the important parameters needed to model its effect on oil recovery.

A New Insight into Hybrid Surfactant and Low Salinity/Engineered Water Injections in Carbonates Through Geochemical Modeling

Low salinity/engineered water injections (LSWI/EWI) have gained popularity as effective techniques for enhancing oil recovery. Surfactant flooding is also a well-established and commercially-available technique in the oil and gas industry. In this paper, a numerical 2D simulation model was developed to investigate the effect of hybrid surfactant-LSWI/EWI on oil recovery from carbonate cores under harsh conditions. The developed simulation model was validated by history-matching recently conducted surfactant corefloods in the secondary mode of injection. Oil recovery, pressure drop, and surfactant concentration data were utilized. The surfactant flooding model was then coupled with a geochemical model that captures different reactions during LSWI/EWI. The geochemical reactions considered include aqueous, dissolution/precipitation, and ion-exchange reactions. Different simulation scenarios were considered and compared including waterflooding, surfactant flooding, engineered water injection, hybrid surfactant-EWI, and hybrid surfactant-LSWI. Additionally, sensitivity analysis was performed on the hybrid surfactant-EWI process through capturing changes in surfactant injected concentration and adsorption. For the case of LSWI/EWI, wettability alteration was considered as the main mechanism underlying incremental oil recovery. However, both wettability alteration and interfacial tension reduction mechanisms were considered for surfactant flooding depending on the type of surfactant used. The results showed that the hybrid surfactant-EWI altered the wettability and achieved higher oil recovery than that of surfactant-LSWI and other techniques. This highlights the importance of selecting the right combinations of potential ions for a certain reservoir to maximize oil recovery rather than a simple water dilution. The results also highlight the importance of surfactant adsorption and surfactant concentration for the hybrid surfactant-EWI technique. This work provides insights into the application of hybrid surfactant-LSWI/EWI on oil recovery especially in carbonates. The novelty of this work is further expanded through comparing surfactant-LSWI with surfactant-EWI and understanding the controlling parameters of surfactant-EWI through sensitivity analysis.

Impact of 2-Aminonicotinic Acid and/or β-Cyclodextrin on the Morphology of Metal Carbonates (M = Ca2+ and Sr2+) Crystallization

We examined the crystallization impact of the surfactant, 2-aminonicotinic acid and/or β-cyclodextrin on the formation of two anhydrous metal carbonates, MCO3 (M = Ca2+ and Sr2+), from their respective calcium chloride and strontium chloride salts along with NaHCO3 at room temperature. By varying the concentrations of this hybrid surfactant to the concentrations of MCO3 during the preparations and examined their particle sizes by PXRD, FTIR, TGA and SEM. The characterization on these newly formed anhydrous metal carbonates clearly indicated that CaCO3 formed with three different shapes such as truncated calcite, hexagonal calcite and rod shaped aragonite. Whereas, SrCO3 formed with two different shapes such as hexagonal poles and bloom scale bars by varying concentrations of the surfactants. The mixed surfactant certainly made an impact on the metal carbonates formations with different shapes and sizes by varying surfactants concentrations and conditions.