Determinación de la exactitud y la precisión del método analítico para la separación y cuantificación de compuestos saturados, aromáticos, resinas y asfaltenos (SARA), en crudos extra-pesados y medianos implementado por el laboratorio de texas OILTECH S.A.S

Abstract

The accuracy and precision of the analytical method for the separation and quantification of saturated, aromatic, resins and asphaltenes (SARA) compounds in extra-heavy, heavy and medium crudes was determined, using the API density as a classification criterion for these crudes. In the present work, the analysis methodology that is implemented by the Texas Oiltech laboratory for the SARA fractionation was pointed out and developed, in order to determine the accuracy and precision; expressed as absolute error and relative error for accuracy, repeatability and reproducibility for precision, necessary analysis parameters for the validation of this method by the laboratory. To determine these parameters, 45 SARA fractionations were carried out by three different analysts on three different days, as well as three crude samples; one as a reference sample called Ecopetrol medium sale castile crude, with a density of 15.1 ° API, another called Capela Extra Heavy crude with a density of 10.0 ° API, and the other sample used was Medium South Blend crude, with a density of 28.0 ° API . Repeatability for this analytical method has values ​​between 0.638 and 0.326%, data expressed as standard deviation, which are equivalent to coefficients of variation between 1.548 and 3.762% with an average of 2.65%. The reproducibility has values ​​between 0.332 and 3.834% as standard deviation, which are equivalent to coefficients of variation between 7.25 and 9.75% with an average of 8.5%, which correspond to the average precision values ​​that can be obtained with the method. . For accuracy, it was determined that the relative error for this quantitative method takes values ​​between the range of 0.18 and 7.73% and the absolute error between 0.06 and 0.78%