Evaluation of the Kinetic and Thermodynamic Behavior of Tracers for Their Applicability in SWCTT

Abstract

Determining residual oil saturation by the single-well chemical tracer test (SWCTT) is of key importance for assessing the potential of enhanced oil recovery (EOR) and developing EOR pilot projects. However, the test trials conducted since the first injections of tracer compositions until now have not resulted in a detailed analysis of the selection of candidates for single-well tracers and their limits of applicability in various reservoir conditions. The purpose of this study was to consider the influence of the structure on the kinetic and thermodynamic components of tracers to assess their application’s operating intervals. It is shown that the rate of single-phase and two-phase hydrolysis of the primary partitioning tracer makes it possible to predict the shut-in time by calculating when the tracer is injected at the reservoir temperature. The influence of the tracer structure during the extraction process with an increase in the hydrocarbon chain of the ester in a different range of brine salinity and temperature has been studied. As a result, this work provides a method for evaluating the thermodynamic and kinetic behavior of primary tracers to establish minimum and maximum threshold K-values at various values of residual oil saturation, temperature, and brine salinity, taking into account the optimal time of the well shut-in to carry out at least 1/2 hydrolysis of esters.