Vapor-phase oxidation of the saturates of crude oil in accelerated-rate calorimetric tests

Abstract

The air injection process (AIP) has long been applied to enhance crude oil production. During an AIP, the injected air reacts in-situ with part of the crude oil, generating heat and flue gas, and thus displacing the other portion of the crude oil. Many field cases have proven that the AIP benefits crude oil production. However, many details of the AIP are not understood. This lack of understanding prevents petroleum engineers from improving the design and results prediction of the AIP. In recent years, the vapor-phase oxidation during the AIP has been discussed. This phenomenon may be essential for the low-temperature oxidation (LTO) of crude oil. However, not many studies on crude oil have directly proven this phenomenon. This paper examines the oxidation characteristics of saturates extracted from crude oil. Using a closed accelerated rate calorimetry (ARC) test allows the liquid-phase and vapor-phase hydrocarbons oxide occur simultaneously. Examining the oxidation characteristics shows that vapor-phase oxidation is the main reaction phase for the saturates of crude oil during LTO.