Experimental study of the performances of commercial surfactants in reducing interfacial tension and wettability alteration in the process of chemical water injection into carbonate reservoirs

Abstract

Surfactants are used in the process of chemical water injection to reduce interfacial tension of water and oil and consequently decrease the capillary pressure in the reservoir. However, other mechanisms such as altering the wettability of the reservoir rock, creating foam and forming a stable emulsion are also other mechanisms of the surfactants flooding. In this study, the effects of three commercially available surfactants, namely AN-120, NX-1510 and TR-880, in different concentrations on interfacial tension of water and oil, the wettability of the reservoir rock and, ultimately, the increase in oil recovery based on pendant drop experiments, contact angle and carbonate core flooding have been investigated. The effects of concentration, temperature, pressure and salinity on the performances of these surfactants have also been shown. The results, in addition to confirming the capability of the surfactants to reduce interfacial tension and altering the wettability to hydrophilicity, show that the TR-880 has the better ability to reduce interfacial tension than AN-120 and NX-1510, and in the alteration of wettability the smallest contact angle was obtained by dissolving 1000 ppm of surfactant NX-1510. Also, the results of interfacial tension tests confirm the better performances of these surfactants in formation salinity and high salinity. Additionally, a total of 72% recovery was achieved with a secondary saline water flooding and flooding with a 1000 ppm of TR-880 surfactant.

Chemical Enhanced Oil Recovery by Different Scenarios of Slug Injection into Carbonate/Sandstone Composite Oil Reservoirs Using an Anionic Surfactant Derived from Rapeseed Oil

“…However, the formed film is not stable due to the reversibility of adsorption of surfactant molecules. In this case, a mixed wettability creates a continuous oil-bed pathway for oil displacement and makes oil production easier …”

“…In this case, a mixed wettability creates a continuous oil-bed pathway for oil displacement and makes oil production easier. 42 Contact angle test is the most common way to represent wettability. However, in this experiment, the rock surface is assumed to be ideal.…”

Effect of a synthesized anionic fluorinated surfactant on wettability alteration for chemical treatment of near-wellbore zone in carbonate gas condensate reservoirs

“…The mechanism of rock wettability alteration is explained by the film formed on the rock surface. Surfactant molecules form a thin film on the rock surface that can form an opposite wettability to the previous state due to its stability and the orientation of the molecules on the surface (Salathiel 1973;Nowrouzi et al 2020b;Najimi et al 2019). The properties of this film depend on the adsorption of surfactants and the formation of hemi-micelles.…”

Oil Recovery Performance by Surfactant Flooding: A Perspective on Multiscale Evaluation Methods

“…Oil–water IFT results obtained by Najimi et al using formation water and crude oil. Reproduced with permission from ref . Copyright 2020 Springer Nature.…”

“…Coreflooding experiments with a 5000 ppm surfactant solution in distilled water showed 8.4% and 6.2% improvements in oil recovery from sandstone and carbonate Iranian rocks, respectively. Three commercial surfactants (AN-120, NX-1510, and TR-880) were evaluated experimentally by Najimi et al 128 for their potential in EOR applications in carbonate rocks. Crude oil of 29°API gravity and formation water of 132 224 ppm TDS from the Sarvestan Iranian oilfield were used along with synthetic brines of varying salinity.…”