A Practical and Economically Feasible Surfactant EOR Strategy: Impact ofInjection Water Ions on Surfactant Utilization

摘要

A comprehensive chemical enhanced oil recovery (CEOR) laboratory evaluation program was carried outto compare surfactants for alkali-surfactant-polymer (ASP) and surfactant-polymer (SP) implementationin a giant Middle East sandstone oil reservoir.The efficacies of ASP and SP floods were investigated inlaboratory corefloods and simulations with emphasis on surfactant retention to improve techno-economicfeasibility.ASP and SP flooding processes were designed with low operational cost in mind and tested in laboratorycorefloods.Different injection water salinities were considered for practical field application.The handlingand availability of injection water with a suitable composition has significant implications in CEOR projects.SP design using produced brine with minimum water treatment is an attractive option for commercialdeployment.We considered different injection water salinities,surfactant molecules,and brine treatmentrequirements for several ASP and SP designs.ASP and SP corefloods recovered nearly all of the remaining oil after waterflooding.The surfactantretention was lower for SP floods when brine with reduced concentration of Ca2+ and Mg2+ (hardness) wasused.Both ASP and SP formulations were also tested for crude oil samples from different zones.A minimaladjustment in injection salinity was required for different oils with our surfactant formulations.Surfactantsdesigned for easy manufacturing and supply availability performed well with brine compositions that requireminimal treatment.Field implementation strategies were evaluated via numerical simulation.The effect ofstrong aquifer drive on SP performance was shown to be minimized with optimized injection/productionstrategies.SP was shown to be technically and economically an attractive candidate tertiary process.