Oxidation Reactions of a Light Crude Oil and Its SARA Fractions in Consolidated Cores

Abstract

Preliminary investigations have been made into the oxidation behavior of a North Sea light crude oil and its individual SARA fractions (saturates, aromatics, resins, and asphaltenes) in the presence of consolidated cores. These investigations were made in an attempt to determine the following: (1) the feasibility of air injection into deep light oil reservoirs, (2) the extent of any interactions between the fractions in a whole oil sample by comparing the behavior of pure fractions with the behavior of mixtures of these fractions in the crude oil. A DISC reactor (an oxidation cell) has been used to study the various oxidation reactions and kinetics of a light oil under high pressure and a constant heating rate, by following the concentrations of the gases evolved (CO 2 , CO) and consumed (O 2 ). Such an investigation allows a quantitative study of the temperature intervals at which evaporation, oxidation, and combustion effects operate for each fraction. The data from these experiments may be used to assist the development of a comprehensive simulator for thermal oil recovery. One aim of the overall work is to replace the conventional two pseudo component representation of crude oil (heavy and light) by a SARA representation with its accompanying interaction and interconversion reactions together with the conventional oxidation reactions. This approach should provide a more realistic representation of the oil oxidation process.

Quantification of low‐temperature oxidation of light oil and its SAR fractions with TG‐DSC and TG‐FTIR analysis

“…In addition, the heat production of crude oil at the LTO and FD phases is in a good agreement with that of saturates in the DSC tests, though the heat release of crude oil at the HTO stage is greatly influenced by aromatics and resins. This finding is consistent with those reported by AlSaffar et al…”

“…As such, it is an effective method to quantify the oxidation characteristics of crude oil by analyzing that of its individual fraction. This finding is consistent with those documented elsewhere …”

“…After the reservoir temperature is increased due to the heat production, the oxidation of saturates is enhanced and gradually dominates the LTO. The content of saturates in a light crude oil is dominant and ensures the stable oxygen consumption during air flooding …”

“…However, both the main components involved in the LTO reaction and the differences associated with the oxidation characteristics among different components have not been well understood. To quantify the oxidation characteristics of crude oils, thermal analysis such as thermogravimetric analysis and differential scanning calorimetry (TG‐DSC), pressure differential scanning calorimetry (PDSC), and thermogravimetric analysis coupled with Fourier transform infrared spectrometer (TG‐FTIR) have been applied to investigate the oxidation properties of crude oil and its SARA fractions, as summarized in Table . Also, this table tabulates the reaction modes and characteristics during the combustion of light and heavy oils, the kinetics and thermochemical parameters of each reaction mode, the differences of oxidation characteristics between light, medium, and heavy oils, the oxidation relationship of crude oil and SARA fractions during the combustion process, and the combustion process of asphalt binder and its SARA fractions, respectively.…”

Kinetic Models for Low Temperature Oxidation Subranges based on Reaction Products

“…In nearly all of the models generated within these studies, the LTO zone is considered as a single reactive zone (Babu and Cormack, 1984;Mamura, 1995;Al-Saffar et al, 2001;Bin et al, 2010;Fassihi et al, 1990;Dabbous and Fulton, 1974).. In nearly all of the models generated within these studies, the LTO zone is considered as a single reactive zone (Babu and Cormack, 1984;Mamura, 1995;Al-Saffar et al, 2001;Bin et al, 2010;Fassihi et al, 1990;Dabbous and Fulton, 1974)..…”