A Study of Oil Recovery by In-Situ Combustion with the Addition of Water

Abstract

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc. This paper was prepared for the 42nd Annual California Regional Meeting of the Society of Petroleum Engineers of AIME, to be held in Los Angeles, Calif., Nov. 4–5, 1971. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal provided agreement to give proper credit is made. Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines. Abstract The object of this work was to improve the forward combustion process by injecting water simultaneously with air. One of the methods used to recover oil from underground reservoirs that has gained interest in recent years is in-situ combustion. This process involves ignition of the oil in reservoir rock and the propagation of the resultant combustion zone propagation of the resultant combustion zone toward producing wells by the injection of air. However, at the present time this method has enjoyed only marginal economic success in a limited number of applications. To study this process, a combustion tube was packed with oil, water, sand and clay. Combustion was initiated and propagated down the tube by the injection of air. In three runs water was injected with the air to study its effect. The produced gas and liquids were measured and analyzed. The temperature and rate of advance of the combustion front were also measured. Pressures at the inlet, outlet and points along the tube were measured throughout points along the tube were measured throughout the run. It was found that adding water to the injected air effected the oil recovery. In all cases where water was injected, oil recovery increased. The rate of oil recovery also increased. More efficient utilization of heat also took place because of the movement of heat from behind the combustion zone to the oil zone ahead of the combustion zone. Introduction Among the methods to recover oil from underground reservoirs that have gained interest in recent years are those involving the application of heat to the reservoir. The use of heat to increase production rate and recovery is not new, however. Shortly after the completion of the Drake well in 1859, steam was used to melt paraffin from the wellbore and increase the rate of paraffin from the wellbore and increase the rate of oil production. In 1935, the Russians were conducting experiments to recover more oil by a process they called crude oil gasification. This process they called crude oil gasification. This work involved moving heat outward from a wellbore into a formation and was the forerunner of an oil-recovery mechanism known today as in-situ combustion. In-situ combustion has, however, met with only marginal economic success in displacing oil from reservoir rock and has found limited application. One reason for this has been poor utilization of the generated heat. Most of the heat is left in the burned portion of the reservoir. One advantage gained from the application of heat to a reservoir is based on reduction of crude oil viscosity at the higher temperature. For the lower gravity oils this is a substantial decrease.