Development of simulation model for the movements of natural partitioning tracers (NPIT) in order to determine residual oil saturation

In this research, the leaching of the partitioning compounds was studied through the analytical model. It was recognized that the late section of concentration curve can be expressed under linear relation with elapsed time and the inclination is governed mainly by partitioning coefficient Kd and residual oil saturation Sor. Based on those findings, the novel method for determination of Sor was proposed by linearization of the late concentration curves of the set from 3 compounds with different Kd values. The proposed linearization method has been validated by 4 experiments on packed column and 8 numerical models. The results showed that the differences in values of Sor obtained by the proposed method and that of models are in the range from 3% to 20%, which are reasonable in comparison with other methods. The analytic procedures of 22 alkyl phenols 6 aliphatic acids in produced water were developed with the detection limit from 0.1-0.4 µg/L which are applicable to analyze the organic compounds in the real reservoirs of concentration of hundreds µg/L. (author)