Field Applications of Interwell Tracers for Reservoir Characterization of Enhanced Oil Recovery Pilot Areas

Abstract This paper presents the results of interwell tracer field work carried out in the McClesky sandstone in conjunction with a surfactant polymer flood pilot, a Dundee limestone pilot designated for an in-depth permeability modification treatment, and a Potter sand steam drive pilot. The objectives were to delineate fluid migration in the reservoirs and to compare tracer performance by co-injection. SCN was the best tracer in the sandstone with recoveries above 90%. In both the McCleskey and the Dundee, tritiated water recoveries were above 75%, with evidence of tritium – hydrogen exchange. Co57 and Co60 recoveries ranged from 35 to 55%. Tertiary butanol recoveries were near 75%, while about 50% of the injected isopropanol was recovered. The performance of ethanol, methanol and methyl ethyl ketone in the Dundee was similar to that of isopropanol. Residual oil saturations in the waterflood areas were measured using interwell tracers. The above alcohols and ionic salt tracers were used in the steam flood as vapor and water tracers, respectively. Strong signatures were observed for the alcohols, but the ionic tracer signatures were erratic.