Chemical Aspects of In-Situ Combustion - Heat of Combustion and Kinetics

Abstract

General remarks on the oxidation reactions of hydrocarbons involved in in-situ combustion are followed by estimates of heat releases. A formula is derived for computing the heat of combustion in the high-temperature zone. Reaction kinetics in porous media applied to the in-situ combustion porous media applied to the in-situ combustion process is discussed. It is observed that there is process is discussed. It is observed that there is some similarity between the kinetics of reverse and partially quenched combustion processes. The influence of additives on crude oil oxidation in porous media is illustrated by effluent gas analysis experiments. Some information concerning the values of the kinetic parameters of the reaction controlling the velocity of a reverse combustion front is derived from the interpretation of laboratory experiments, using a numerical model. Introduction A great deal of laboratory and field work has been done on thermal recovery methods. The importance and limitations of these techniques have been extensively studied. However, some of the chemical and physical problems involved that needed to be elucidated were studied as part of a research program carried out by the Institut Francais du Petrole. Specific problems are created by in-situ combustion since both the possibility of combustion-front propagation and the air requirement are controlled by the extent of the exothermic oxidation reactions. Actually, the propagation velocity of a forward combustion front depends on the fuel formation and combustion, which are controlled by the kinetics of these processes; furthermore, the peak temperature is related to the heat released by oxidation and combustion reactions. Therefore, a quantitative estimation of the parameters related to the chemical aspects of the parameters related to the chemical aspects of the process is a necessary step in studying combustion process is a necessary step in studying combustion through a porous medium. General and theoretical considerations on heats of reaction and kinetics are presented and illustrated by experimental data and numerical interpretation of the results. HEAT RELEASED IN THE OXIDATION OF HYDROCARBONS DESCRIPTION OF OXIDATION REACTIONS A great number of reaction products are produced by the oxidation of hydrocarbons. By taking into account the formation of bonds between one carbon atom and oxygen, it is possible to derive the most important processes. Complete combustion, (1) 2 2 2 2H H3R C R + ---- O → RR + CO + H O Incomplete combustion, (2) 2 2H H R C R + O → RR + CO + H O Oxidation to carboxylic acid, (3) 2 2 2H OH H3 OR C H + --- O → R - C + H O Oxidation to aldehyde, (4) H H R C Oxidation to ketone, (5) 2 2H O H R C R ' + O → R - C - R; + H O Oxidation to alcohol, (6) R' R; R C H SPEJ p. 410

Influence of rock matrix in air kinetics oxidation for heavy oils

“…Fassihi (1981) confirmed the catalytic effect of clays when observing a decrease in the activation energy in the combustion reaction for a test, in which he added 5% of clay to the sand, compare to a test in which only sand was used. This same effect was observed by Bardon & Gadelle (1977) and Burger & Sahuquet (1972).…”

In-Situ Combustion Handbook -- Principles and Practices

“…Those reactions which occur at temperatures below 400"F are defined as the low temperature oxidation (LTO) and the other being the high temperature oxidation (HTO). Unlike the HTO, which produces COZ, CO, and water (HZO) as its primary reaction products, LTO yields water and partially oxygenated hydrocarbons such as carboxylic acids, aldehydes, ketones, alcohols, and hydroperoxides (Burger et al, 1972).…”

Performance Evaluation of Thermal Enhanced Oil Recovery by In-situ Combustion

“…In addition to the above conditions, ISC is accepted that the process is economically inexpensive method in the following reservoir conditions (Burger, 1972a(Burger, , 1972bBrigham, 2006;Turta, 1994): ➢ In shallow reservoirs ISC is a very effective method but it is complicate, and it can be used for a shallow reservoir for recovering the 10-20°API heavy oil in which conventional techniques cannot be succeeded due to the oil density. ➢ In deep reservoirs improving the recovery of light oil about >30°API.…”