A Study of the Sensitivity of Oil Recovery to Production Rate

Abstract

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc. This paper was prepared for the 49th Annual Fall Meeting of the Society of Petroleum Engineers of AIME, to be held in Houston, Texas, Oct. 6–9, 1974. 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 discussions may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines. Abstract With the world wide high demand for oil, the rate of oil production from Alberta pools has dramatically increased over the last few years. This investigation was undertaken to determine if reservoirs, typical of the more important Alberta pools, are sensitive to production rate within reasonable economic limits of production. Sensitivity to rate is defined as the ultimate economic recovery being adversely affected by increasing withdrawal rates. Results of the study showed that the reservoirs were not sensitive to production rate insofar as reservoir mechanics were concerned. That is, given reasonable economic parameters and good field operating practice, the ultimate recovery was not adversely affected by increasing production rate. In fact, the studies showed that production rate. In fact, the studies showed that higher ultimate recovery was obtained at higher producing rates. Introduction As production rates in Alberta have increased to meet high market demand, it has been proposed that in many cases increasing production rate can adversely affect ultimate recovery. This rationale is in turn, partly derived from observations that counter-current imbibition and gravity drainage are time-dependent recovery mechanisms and can more effectively contribute to ultimate recovery at lower reservoir withdrawal rates. This paper describes results of a study to determine the effects on oil recovery of production rate. The study was constrained production rate. The study was constrained to determination of rate effects solely from the point of view of reservoir fluid mechanics. Besides reservoir flow mechanics considerations, operational strategies and constraints will affect ultimate recovery. For example, the type of water-flood pattern implemented, injectivity and productivity limitations, the allocation of production among wells and complex economic limit considerations at abandonment will affect ultimate recovery. Such operational considerations are outside the scope of this study and do not affect the rate sensitivity conclusions as they relate to reservoir fluid mechanics.