Study of Oxidation Reactions in A Light Oil Carbonate Reservoir for High-Pressure Air Injection Process

Abstract

Air injection-based processes have drawn attention over the years as an enhanced oil recovery (EOR) technique due to the high thermal efficiency and the unlimited availability and low cost of the air. A key challenge for the application of the process is the poor understanding of the reaction kinetics. Without reliable knowledge about the mechanics of the kinetic reaction, the performance of the air injection-based EOR process cannot be accurately predicted. Experimental studies are necessary to understand various aspects of the mechanisms of the process. This study focuses on the study of chemical reactions and their kinetics in a light oil carbonate reservoir in Mexico. Two air injection thermal analysis techniques were used: Accelerating Rate Calorimeter (ARC) and Ramped Temperature Oxidation (RTO). Five ARC tests and three RTO tests were performed on oil and core samples from the target reservoir to analyze the behaviour of a dolomite core and fluid system while injecting air. Based on the analysis of the experimental data, it was concluded that the studied reservoir is suitable for the application of the High-Pressure Air Injection process. ARC tests demonstrated that the oil and core system was reactive and the reactivity of the oil during isoage tests suggested the reservoir was a candidate for self-ignition. RTO tests evaluated the oxidation characteristics of the oil. The temperature range where the oil and core reacted with air in all the experiments corresponded to bond-scission reactions for light oils. Calculations of kinetic parameters are discussed in this study.