Enhanced crude oil recovery by chemical flooding has been a main measure for postponing the overall decline of crude oil output in China, and surfactant‐polymer (SP) flooding may replace alkali‐surfactant‐polymer flooding in the future for avoiding the undesired effects of using alkali. In this paper the synthesis of a surfactant with a large hydrophobe, didodecylmethylcarboxyl betaine (diC12B), and its adaptability in SP flooding were investigated. The results show that diC12B can be synthesized by reaction of didodecylmethyl amine, a product commercially available, with chloroacetic acid in the presence of NaOH, with a resulting yield as high as 80 wt% under appropriate conditions. With double dodecyl chain diC12B is highly surface active as displayed by its low CMC, 3.7 × 10−6 mol L−1, low γCMC, 27 mNm−1, as well as high adsorption and small cross section area (≤0.25 nm2) at both air/water and oil/water interfaces at 25 °C. By mixing with conventional hydrophilic surfactants diC12B can be well dissolved in Daqing connate water and reduce the Daqing crude oil/connate water interfacial tension to about 10−3 mN m−1 at 45 °C in a wide total surfactant concentration range, from 0.01 to 0.5 wt%. And a tertiary oil recovery, 18 ± 1.5 % OOIP, can been achieved by SP flooding using natural cores without adding any alkaline agent or neutral electrolyte. DiC12B seems thus to be a good surfactant for enhanced oil recovery by SP flooding.
Natural gas foam can be used for mobility control and channel blocking during natural gas injection for enhanced oil recovery, in which stable foams need to be used at high reservoir temperature, high pressure and high water salinity conditions in field applications. In this study, the performance of methane (CH 4 ) foams stabilized by different types of surfactants was tested using a high pressure and high temperature foam meter for surfactant screening and selection, including anionic surfactant (sodium dodecyl sulfate), non-anionic surfactant (alkyl polyglycoside), zwitterionic surfactant (dodecyl dimethyl betaine) and cationic surfactant (dodecyl trimethyl ammonium chloride), and the results show that CH 4 -SDS foam has much better performance than that of the other three surfactants. The influences of gas types (CH 4 , N 2 , and CO 2 ), surfactant concentration, temperature (up to 110 C), pressure (up to 12.0 MPa), and the presence of polymers as foam stabilizer on foam performance was also evaluated using SDS surfactant. The experimental results show that the stability of CH 4 foam is better than that of CO 2 foam, while N 2 foam is the most stable, and CO 2 foam has the largest foam volume, which can be attributed to the strong interactions between CO 2 molecules with H 2 O. The foaming ability and foam stability increase with the increase of the SDS concentration up to 1.0 wt% (0.035 mol/L), but a further increase of the surfactant concentration has a negative effect. The high temperature can greatly reduce the stability of CH 4 -SDS foam, while the foaming ability and foam stability can be significantly enhanced at high pressure. The addition of a small amount of polyacrylamide as a foam stabilizer can significantly increase the viscosity of the bulk solution and improve the foam stability, and the higher the molecular weight of the polymer, the higher viscosity of the foam liquid film, the better foam performance.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.