A Prediction Method for Reservoir Flooding with Fluids of Reduced Mobility

Abstract

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 Although prediction methods are available for water flooding and gas flooding in oil reservoirs, none exists for flooding with fluids of reduced mobility. These new flooding methods are so different and so much more complicated than water flooding that the methods which are used for predicting water flooding are predicting water flooding are inadequate. The calculation method described here employs a linear, layered reservoir model to simulate processes involving flooding with a fluid of reduced mobility. The model is able to account for non-unit water-oil mobility ratio, the variation in permeability of the reservoir rock, permeability of the reservoir rock, the slug size of the reduced mobility fluid, the retarded flow rate of the reduced mobility fluid, and the reduction in mobility of the injected fluid. The present model is designed specifically for floods which are initiated as reduced mobility floods. This paper presents the mathematical development of the model and a graphical presentation of the results of calculations presentation of the results of calculations based on the model. With the set of graphs, a user can prepare flooding predictions for various slug sizes of the reduced mobility fluid for economic analysis. Introduction Many methods such as those of Buckley-Leverett, Dykstra-Parsons, Hurst, etc., predict water flood response in oil reservoirs. However, none of these can conveniently account for the complexities introduced by flooding with fluids of reduced mobility. In these cases, a zone of reduced mobility is created near the injection well by the injection of a slug of fluid containing additives such as a water soluble polymer or other materials producing a similar reduction in mobility. Although the properties of these slugs may vary with properties of these slugs may vary with time and position, they can be modeled sufficiently well that their influence on oil recovery can be predicted for comparison with the results of other flooding methods. This paper describes such a model and gives the results of calculations based on it.