Synergistic Effects between Anionic and Sulfobetaine Surfactants for Stabilization of Foams Tolerant to Crude Oil in Foam Flooding

Abstract

In foam flooding, foams stabilized by conventional surfactants are usually unstable in contacting with crude oil, which behaves as a strong defoaming agent. In this article, synergistic effects between different surfactants were utilized to improve foam stability against crude oil. Targeted to reservoir conditions of Daqing crude oil field, China (45 C, salinity of 6778 mg L −1 , pH = 8-9), foams stabilized by typical anionic surfactants fatty alcohol polyoxyethylene ether sulfate (AES) and sodium dodecyl sulfate (SDS) show low composite foam index (200-500 L s) and low oil tolerance index (0.1-0.2). However, the foam stability can be significantly improved by mixing the anionic surfactant with a sulfobetaine surfactant, which behaves as a foam stabilizer increasing the half-life of foams, and those with longer alkyl chain behave better. As an example, by mixing AES and SDS with hexadecyl dimethyl hydroxypropyl sulfobetaine (C 16 HSB) at a molar fraction of 0.2 (referring to total surfactant, not including water), the maximum composite foaming index and oil tolerance index can be increased to 3000/5000 L s and 1.0/4.0, respectively, at a total concentration between 3 and 5 mM. The attractive interaction between the different surfactants in a mixed monolayer as reflected by the negative β s parameter is responsible for the enhancement of the foam stabilization, which resulted in lower interfacial tensions and therefore negative enter (E), spreading (S), and bridging (B) coefficients of the oil. The oil is then emulsified as tiny droplets dispersed in lamellae, giving very stable pseudoemulsion films inhibiting rupture of the bubble films. This made it possible to utilize typical conventional anionic surfactants as foaming agents in foam flooding.

A study on the bio-based surfactant sodium cocoyl alaninate as a foaming agent for enhanced oil recovery in high-salt oil reservoirs

“…The foam comprehensive index (FCI) was then used to evaluate the foam quality with the consideration of both foaming ability and foaming stability. [46][47][48][49][50][51] The FCI value was calculated as FCI = 0.75V F $t 1/2 . The higher the FCI value, the better the foam quality.…”

Progress in research of sulfobetaine surfactants used in tertiary oil recovery

“…Because of the connection between carbon atom and sulfur atom on the sulfonic acid group, sulfobetaine surfactants are not easy to hydrolyze under high temperature and acidic environments (Liu et al, 2021a; Liu et al, 2021b). In addition, in almost all pH ranges, sulfobetaine surfactants do not accept or release protons (Pal & Sahu, 2022; Phukon & Sahu, 2017).…”

“…In addition, it was found that the way to improve the wettability alteration is to increase salinity and alkalinity (Kumar & Mandal, 2019). Sulfobetaine surfactants, as important zwitterionic surfactants, have become one of the TOR research priorities because of their stable performance, excellent resistance to high concentrations of acid, alkali, salt and high temperature, and good synergy with other surfactants, polymers and other chemical additives (Chen et al, 2021;Guo et al, 2014;Liu et al, 2021aLiu et al, , 2021b.…”

Synergisms between Surfactants, Polymers, and Alcohols to Improve the Foamability of Mixed Systems

“…For this reason, the kinetic stabilization of foams is required. Because of the synergistic effect with low molecular weight surfactants [13], polymers have been used as additives in foaming solutions to stabilize the foam, since polymers can also adsorb at the interfaces [11,14].…”