A great deal of information has been published on the use of surfactants in CO2 foam published on the use of surfactants in CO2 foam flooding applications. However, generally the chemical composition of the surfactant has not been specified and little work describing the relationship of surfactant chemical structure and physical properties to foaming agent performance physical properties to foaming agent performance has been reported. This laboratory study examines the performance of more than 40 surfactants in 1 atmosphere foaming experiments. Several classes of surfactants were studied including alcohol ethoxylates, alcohol ethoxysulfates, alcohol ethoxyethylsulfonates and alcohol ethoxyglyceryl-sulfonates. Surfactants which performed well in the 1 atmosphere (1.01 × 105 Pa) foaming experiment were also good foaming agents in sight cell and core flood experiments performed in the presence of CO2 and reservoir fluids under realistic reservoir temperature and pressure conditions. Introduction Many miscible floods have exhibited early breakthrough of injected fluids and concomitant poor volumetric sweep efficiency and lower than poor volumetric sweep efficiency and lower than predicted oil recovery. Viscous fingering of predicted oil recovery. Viscous fingering of fluids has been studied extensively in the laboratory. Water-alternate-gas (WAG) injection to decrease carbon dioxide (CO2) mobility has been widely used. Stalkup has reviewed results of several CO2 floods and concluded that the WAG process was only "partially successful in process was only "partially successful in moderating CO2 production." Other methods of increasing the injected gas breakthrough time and reducing the produced gas:oil ratio (GOR) include zone isolation, decreasing the gas injection rate, and use of horizontal injection and production wells. production wells. The use of foams to reduce CO2 mobility was initially patented by Bernard and Holm and has been the subject of a number of publications since that time. Foam exhibits higher apparent viscosity and lower mobility within a formation than its separate constituents. This lower mobility may often be achieved by the inclusion of less than 0.01% surfactant in the liquid phase of the foam. Among the surfactants phase of the foam. Among the surfactants that have been studied for miscible gas mobility control are ethoxylated alcohols particularly those in the C12-15 range, sulfate and sulfonate esters of ethoxylated linear alcohols, alkylphenol ethoxylates, and low molecular weigh ethylene oxide—propylene oxide copolymers. While 1 atmosphere foaming experiments permitted the screening of large numbers of permitted the screening of large numbers of surfactants, conclusions drawn from data were often not specific enough to permit surfactant optimization. Often, results were not extended to study foam behavior under realistic reservoir conditions. Design and optimization of chemical structure and compositions of foaming agents in the presence of brines and crude oil under realistic reservoir temperature and pressure conditions has been carried out by Wellington. During the course of this work, he developed a one atmosphere foam stability screening test. In this paper, the one atmosphere screening test (modified as described below) is used to relate surfactant foaming properties to chemical structure, to rank large numbers of surfactants in terms of foam stability and to observe the foam sensitivity to the presence of crude oil, aqueous fluid salinity and pH, and temperature. The best surfactants were then studied under reservoir temperature and pressure conditions using a sight cell and pressure conditions using a sight cell and evaluated further using carefully designed core flood experiments.
No abstract
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.
customersupport@researchsolutions.com
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.