Use of Incremental Analysis in the Operations of Cyclic Steam Projects

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. In a cyclic steam [push-pull] project, the operator is faced with a continuous job of deciding which well should be resteamed next. To maximize the profit from a project, the changes in annual oil production and annual steam requirements, resulting from changing the frequency of steaming of each possible steam candidate, should be determined. The most desirable candidate is the well that will produce the largest amount of increased oil per produce the largest amount of increased oil per barrel of additional steam required for an increased steaming frequency. A method has been developed to calculate the barrels of incremental oil per barrel of incremental steam for a given well at a given time from the production history of that well. An example of production history of that well. An example of the use of this method in scheduling wells for a generator is included. Comparisons between the results of this method and several other methods of choosing steam candidates are presented. Examples are included to illustrate presented. Examples are included to illustrate how the method can be adapted to determine the economics of expanding a project by adding wells or steam generators. Introduction This paper is an attempt to illustrate how results of cyclic steam projects can be improved by the analysis of the production history of each individual well in the project. After all the wells connected to a steam generator have been steamed for the first time, the operator is faced with the continuing job of examining the results of previous cycles and deciding which well should be steamed next. Each of the possible choices has a positive factor (the oil that would be produced on another cycle] and a negative factor [the oil that would be produced if the present cycle were continued]. As the cycle length is changed, both of these factors change. The problem boils down to choosing which well will have the largest positive difference at the time a steam candidate is required. While wide variations in the response to steam from supposedly similar wells are invariably found in cyclic steam projects, succeeding cycles on an individual well will be similar and predictable with a reasonable degree of predictable with a reasonable degree of accuracy in the majority of cases. By plotting the production history of a well and mathematically fitting a curve through this history, the performance of the well is represented by an equation relating cumulative production and time and can be extrapolated production and time and can be extrapolated [Fig. 1]. Increasing the frequency of steaming will result in an increased number of shorter cycles.