Some Fundamentals of Steam-Plateau Behavior in Combustion Oil Recovery
Authors: Penberthy W.L. , Berry H.J. , Ramey H.J. 
Published: December 2007

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc.
This paper was prepared for the 43rd Annual Fall Meeting of the Society of Petroleum Engineers of AIME, to be held in Houston, Tex., Sept. 29-Oct. 2, 1968. 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 paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal provided agreement to give proper credit is made. 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
Much experimental work has been done in the field and in the laboratory on the forward-combustion oil recovery process. Yet very little information is available concerning the associated steam plateau. Only preliminary and unsatisfactory attempts have been made to describe it. Moreover, the current literature is controversial as to both the existence and the importance of the steam plateau in forward-combustion oil recovery.
The combustion-tube experiments described in this paper demonstrated that the steam plateau does exist and that it moves ahead of the burning front. An analytical heat model was developed to describe the axial movement of the steam plateau in a cylindrical system and the temperature distribution along the leading edge of the plateau. The solution of the model provided a means of further studying the steam provided a means of further studying the steam plateau and permitted the estimation of the plateau and permitted the estimation of the effective thermal diffusivity in this region. There was favorable agreement between measured experimental time-temperature-distance profiles and those generated by the heat model.
In addition to confirming the existence of the steam plateau, a comparison and analysis of experimental and analytical results also revealed that: the temperature of the steam plateau is principally controlled by phase plateau is principally controlled by phase equilibrium; the temperature within and movement of the steam plateau is related to the vaporization and condensation of water rather than hydrocarbons; the temperature level of the steam plateau is related to air injection pressure and to a lesser degree to the initial pressure and to a lesser degree to the initial water saturation; heat loss from the steam plateau may limit the size of the steam plateau plateau may limit the size of the steam plateau so that it moves at the same velocity as the burning front, both conduction and convection are important heat transfer modes; and the steam plateau is the temperature base for the burning-front phenomena.

Introduction
A considerable amount of work has been done on the forward combustion oil recovery process, and numerous investigators have reported the results of combustion-tube studies as well as experimental results from field tests. However, no complete theory of the forward-combustion process is yet available. As a result of laboratory investigations, many of the important features of the forward-combustion process are well known; sufficiently so that several process are well known; sufficiently so that several investigators have attempted to describe the movement of heat and fluids analytically.