Calculation of oil recovery by continuous steam injection is generally tedious, even if a computer program is used for this purpose. The present study is directed toward developing a graphical method of computation of oil recovery by continuous steam injection in a five spot pattern. Oil recovery from the steam-invaded zone as well as from the condensate zone ahead of the steam zone is considered in this treatment. Expansion of the steam zone and t temperature variation of density are employe compute the effective flood advance rate for the hot and cold waterflood zones ahead of the steam zone, in which Buckley-Leverett type displacement is assumed to occur. One of the basic parameters involved in the method is the parameters involved in the method is the steamflood sweep efficiency, which is based upon detailed theoretical and experimental investigations. Along with the detailed graphs, the basic equations used are also presented, in case it is desired to use the present method on a digital computer.
The end product of the computation technique presented is a curve of cumulative oil recovery presented is a curve of cumulative oil recovery vs. time. Curves of this type computed by the proposed technique are compared with experimental proposed technique are compared with experimental curves, as well as with values predicted by detailed methods, showing fair agreement.
In recent years, steam injection has come to be recognized as an important oil recovery method. Most of the projects have so far utilized cyclic steam injection, which, in spite of its attractive feature of quick return, is basically a formation stimulation type operation marked with a low ultimate oil recovery of 6-15% of the oil in place. For this reason, increased interest is being shown in steamflooding, or continuous steam injection, with operational features similar to those for waterflooding, in order to enhance the ultimate oil recovery.
A member of methods have been proposed for the computation of oil recovery by a steamflood, the most notable being those due to Marx and Langenheim, Ramey, and Willman et al. Recently, Davies, Silberberg, and Caudle presented a method for predicting oil recovery from a five-spot steamflood, in which streamlines were approximated by straight lines radiating from the injection well, and converging to the production well. The present work develops a method production well. The present work develops a method for predicting the performance of a steamflood in a five-spot pattern, employing a combination of Marx and Langenheim's, Willman et al's, Ramey's, and Higgins and Leighton's techniques.