Thermogravimetric and differential thermogravimetric analysis of effect of areal compositional gradient on combustion kinetics of Mexican extra-heavy crude oil

Numerous studies have contributed to a better understanding of the in-situ combustion process that have allowed to determine the most suitable conditions to carry out this process in reservoirs from volatile to extra-heavy crude oils. One of the elements that alter the behavior of this process is the compositional gradient. In this work, the effects of areal compositional variations in the in-situ combustion of three Mexican extra-heavy crude oil samples obtained from the same reservoir and extracted under similar production conditions were studied. Physicochemical, thermal, and kinetics analyses (by means of one non-linear method) were carried out to study the areal compositional variations of the extra-heavy crude oil samples, and their effect on the in-situ combustion of this type of crude oil was also analyzed. Physicochemical characterization includes measurements of viscosity, density, water content, and SARA content. Thermal analyses were performed using three heating rates (5 °C/min, 10 °C/min, and 15 °C/min), while kinetic analyses were calculated using Friedman’s method.