Theoretical and experimental investigation of effect of salinity and asphaltene on IFT of brine and live oil samples

Abstract

Several factors influence the IFT of oil and formation water. These factors are rooted in the complex composition of oil, presence of different salts in water, water salinity, temperature, and pressure of reservoir. In the first part of this paper, effect of salinity on IFT between brine and an Iranian live oil sample has been studied experimentally. It is observed that IFT increases almost linearly with brine concentration. Also, linear increasing behavior of IFT with respect to pressure is obviously seen. Then, using thermodynamic properties such as surface excess concentration, chemical potential, chemical activity, and activity coefficient, results were analyzed and observed effect of salinity and pressure were justified thermodynamically. In the second part, the effect of asphaltene on IFT reduction has been studied. In previous works, the investigators extracted resin and asphaltene and then examined their effects on IFT in the absence of other fractions of oil phase. We believe that all fractions play a role in this phenomenon so, in this paper, the effect of natural surfactants of oil phase on IFT has been investigated in presence of all fractions of oil. Hence, SARA test was performed on all samples. Then, IFT between oil samples and brine were measured using captive drop instrument at 25 °C and 3000 psia. Results showed that neither asphaltene content nor asphaltene/resin ratio is a good indicator for effect of asphaltene on IFT, whereas colloidal instability index could be a useful tool to predict asphaltene effect on IFT.

Geochemical Impact of High-Concentration Formate Solution Injection on Rock Wettability for Enhanced Oil Recovery and Geologic Carbon Storage

“…The oil/brine IFT was lower than the oil/deionized water IFT. This behavior is consistent with many previous studies, in which the oil/brine IFT was significantly affected by brine composition, salinity, and oil composition. − The result shows that increasing the FM concentration caused a slight reduction in IFT. The 30 wt % FM solutions at different initial pH values, 6.1 and 7.0, had similar IFT values but resulted in markedly different oil recoveries (Figure ).…”

Evaluation of modified cashew nutshell liquid as natural surfactants for chemical flooding in sandstone oil reservoirs

“…Better IFT reduction was achieved with the use of TA-2 surfactant in brines of varied salinities than TA-3 surfactant. Reduction in IFT with increase in brine salinity was observed with the use of TA-2, while increase in IFT with increase in salinity was observed with TA-3 indicating that there is a relationship between brine salinity and interfacial tension of the oleic-aqueous system, and it is dependent on the type of salt, amount of salt, type, and concentration of surfactant present [37]. This further showed the tolerance and efficiency of TA-2 surfactant in saline environments.…”

Effects and Mechanisms of Acidic Crude Oil–Aqueous Solution Interaction in Low-Salinity Waterflooding

“…Interfacial tension (IFT) is usually used as the intensity criteria of fluid–fluid interactions and as one of the dominant mechanisms for EOR in low-salinity waterflooding, as reported by Mokhtari et al., , Tetteh et al, − and Farhadi et al However, due to the experimental differences, some controversial conclusions have been proposed. For ion amount, Ikeda et al, Barati-Harooni et al, and Soleymanzadeh et al reported that an increase in salinity resulted in an increase in IFT. Correspondingly, Okasha and Alshiwaish and Yousef et al observed a general trend of IFT decreases with decreasing salinity.…”