Carboxymethylated Ethoxylated Surfactants: Annual Report

摘要

A method of selecting surfactants for chemical enhanced oil recovery using carboxmethylated ethoxylated surfactants (CES) is described. Structure/performance correlations for hydrophobe, ethylene oxide content, and nonionic-anionic ratio have been developed for a series of CES with alkane carbon number, pH, salinity, phase inversion temperature, and solubilization parameter to provide a guide in selecting candidate surfactants for enhanced oil recovery. Carboxymethylated ethoxylated surfactants are a class of surfactants that generate low interfacial tension against crude oils at high temperatures, high salinities and high divalent ion concentrations. Selection of the surfactant for a specific reservoir can be made based upon determination of the phase inversion temperature (PIT) of the surfactant at reservoir salinity with live crude. An additional scan for phase behavior (salinity scan) can then establish salinity tolerance and solubilization parameters for the selected surfactant system. Correlations of PIT with surfactant structure, salinity, and hydrocarbon have been determined for a number of US reservoirs using CES as the only surfactant. 67 refs., 20 figs., 3 tabs. (ERA citation 12:047134)