Frontal-Stability Analysis of Surfactant Floods

Tavassoli, Shayan; Pope, Gary A.; Sepehrnoori, Kamy

doi:10.2118/169118-pa

Cited by 9 publications

(6 citation statements)

References 23 publications

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“…On the other hand, conventional AF and SF can only improve the microscopic sweep efficiency. To examine the displacement efficiency of any enhanced oil recovery technique, particularly chemical flooding methods, a capillary desaturation curve (CDC) is constructed by conducting coreflooding tests at various flow rates [94,95]. A CDC usually reflects the pore structure, arrangement within the porous media, and fluid distribution inside these pores [96].…”

Section: Introductionmentioning

confidence: 99%

Capillary Desaturation Tendency of Hybrid Engineered Water-Based Chemical Enhanced Oil Recovery Methods

et al. 2021

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Several studies have shown the synergetic benefits of combining various chemical enhanced oil recovery (CEOR) methods with engineered waterflooding (EWF) in both sandstones and carbonate formations. This paper compares the capillary desaturation tendency of various hybrid combinations of engineered water (EW) and CEOR methods with their conventional counterparts. Several coreflood experiments were conducted, including EW-surfactant flooding (EWSF), EW-polymer flooding (EWPF), EW-alkali-surfactant flooding (EWASF), EW-surfactant-polymer flooding (EWSPF), and EW-alkali-surfactant-polymer flooding (EWASP). Capillary numbers (Nc) and corresponding residual oil saturation (Sor) for each scenario are compared with capillary desaturation curves (CDC) of conventional CEOR methods from the literature. The results indicate that hybrid EW–CEOR methods have higher capillary desaturation tendency compared to conventional methods. The capillary numbers obtained by standalone polymer flooding (PF) are usually in the range from 10−6 to 10−5, which are not sufficient to cause a significant reduction in Sor. However, the hybrid EW-polymer flooding approach considerably reduced the Sor for the same Nc values, proving the effectiveness of the investigated method. The hybrid EWASP flooding caused the highest reduction in Sor (23%) against Nc values of 8 × 10−2, while conventional ASP flooding reduced the Sor for relatively higher Nc values (3 × 10−3 to 8 × 10−1). Overall, the hybrid methods are 30–70% more efficient in terms of recovering residual oil, compared to standalone EWF and CEOR methods. This can be attributed to the combination of different mechanisms such as wettability modification by EW, ultralow interfacial tension by alkali and surfactant, reduced surfactant adsorption by alkali addition, and favorable mobility ratio by polymer. Based on the promising results, these hybrid techniques can be effectively implemented to carbonate formations with harsh reservoir conditions such as high salinity and high temperature.

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Section: Introductionmentioning

confidence: 99%

Capillary Desaturation Tendency of Hybrid Engineered Water-Based Chemical Enhanced Oil Recovery Methods

et al. 2021

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“…The simulations revealed that gravity stable surfactant floods can be very efficient at horizontal wells in reservoirs with a high vertical permeability [46]. These advantages become significant when the reservoir temperature is high and the use of polymer becomes increasingly difficult.…”

Section: Frontal-stability Analysis Of Surfactant Floodsmentioning

confidence: 99%

“…Recent surfactant-flooding experiments have shown that a very efficient oil recovery can be obtained without mobility control when the surfactant solution is injected at less than the critical velocity required for a gravity stable displacement [46]. A method has been developed to predict the stability of surfactant floods at the reservoir scale on the basis of gravity stable surfactant flooding experiments at the laboratory scale.…”

Section: Frontal-stability Analysis Of Surfactant Floodsmentioning

confidence: 99%

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Enhanced oil recovery

2015

Petroleum Engineer's Guide to Oil Field Chemicals and Fluids

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“…The formation of a microemulsion phase and an oil bank was observed in displacement experiments. Microemulsion properties, especially viscosity, were found to be important for the determination of viscous stability of surfactant floods (Tavassoli et al 2014(Tavassoli et al , 2015. In an unstable displacement with an injection rate above the critical velocity, the formation of fingers was observed (Lu 2014;Tavassoli et al 2014).…”

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confidence: 99%

New Insights into Surfactant Adsorption Estimation in Carbonates under Harsh Conditions Using Surface Complexation Modeling

Khurshid

Al-Shalabi

Afgan

2022

SPE Reservoir Evaluation &Amp; Engineering

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Summary Several laboratory experiments demonstrated that the use of sodium hydroxide could increase the solution pH and reduce the adsorption of anionic surfactants. However, a better understanding of rock-oil-brine interactions and their effect on surfactant adsorption during alkaline-surfactantpolymer (ASP) flooding is needed for realistic and representative estimations of surfactant adsorption levels. Therefore, this study presents a novel approach to capture these interactions and better predict their effect on surfactant adsorption as well as effluent concentrations of surfactant and various aqueous species using the Phreeqc simulator. Currently, surface complexation models (SCMs) consider rock-brine, oil-brine, and surfactant-brine reactions. In this work, four new surface complexation reactions with intrinsic stability constants that honor oil-surfactant interactions have been proposed for the first time and then validated against experimental data reported in the literature. In addition, we analyzed the effect of various parameters on surface adsorption under harsh conditions of high temperature and high salinity using the proposed SCM. The results showed that the developed surfactant-based SCM is capable of estimating surfactant adsorption and its concentration in the effluent during chemical floods. The model was validated against two sets of ASP corefloods from the literature including single-phase and two-phase dynamic surfactant adsorption studies. The findings highlighted that oil-surfactant surface complexation reactions are important and should be captured for a more representative and accurate estimation of surfactant adsorption during chemical flooding. Moreover, the detailed and comprehensive analysis showed that surfactant adsorption increased and its concentration in the effluent decreased with the increase in temperature of the chemical flood. The latter shows that the adsorption process is endothermic and it is more of chemisorption as opposed to physio-adsorption. It was also showed that a decrease in water total salinity decreases the surfactant adsorption on the rock surface, which is related to the increase in the repulsive forces between the rock surface and adsorbed species. Additionally, with the increase in surfactant concentration in the chemical flood, surfactant concentration in the effluent increases, with a slight increase in surfactant adsorption. This slight increase in adsorption can be neglected compared with the injected and produced masses of the surfactant that are proportional. Moreover, the effect of sulfate spiking is significant where the increase in sulfate concentration reduces the surfactant adsorption. Furthermore, it is worth highlighting that the lowest surfactant adsorption levels were achieved through injected water dilution; less than 0.1 mg/g of rock. This is the first study to test a novel formulation of SCM considering the oil-surfactant effect on surfactant adsorption properties. The proposed framework to estimate surfactant adsorption is conducted for high-temperature and high-salinity reservoir conditions. Thus, it could be used in numerical reservoir simulators to estimate oil recovery due to wettability alteration by chemical flooding in carbonates, which will be investigated in our future work. The surfactant adsorption mechanisms during chemical flooding are very case-dependent and hence, the findings of this study cannot be generalized.

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Frontal-Stability Analysis of Surfactant Floods

Cited by 9 publications

References 23 publications

Capillary Desaturation Tendency of Hybrid Engineered Water-Based Chemical Enhanced Oil Recovery Methods

Capillary Desaturation Tendency of Hybrid Engineered Water-Based Chemical Enhanced Oil Recovery Methods

Enhanced oil recovery

New Insights into Surfactant Adsorption Estimation in Carbonates under Harsh Conditions Using Surface Complexation Modeling

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