Published in Petroleum Transactions, AIME, Volume 204, 1955, pages 160–174.
To gain an insight into the deviations from normal behavior caused by dip, a mathematical study has been made of single-fluid five-spot floods in dipping reservoirs for flooding techniques likely to be employed in such cases. Streamline patterns and sweep efficiencies are computed for a number of different cases, and the results, where possible, are presented in graphical form. An increase in sweep efficiency can be obtained by moving the central injection well updip, and the optimum position is found for several cases. The applicability of the results is discussed.
Because of the growing importance of water flooding in California and in other locations where large angles of dip are quite common, it is important to know at least some of the effects of dip on the performance characteristics of water floods in such instances. In the past, only reservoirs having relatively mild dips have been waterflooded. Consequently, little is known today as to the effect of dip on the performance characteristics of a flooding operation from the point of view of field experience; and because of the complexity of the problem, little, if anything, has been done on the problem from the point of view of theory.
There are two distinct aspects of the role played by gravity in a flooding operation. The first is that of the preferential segregation of the reservoir fluids at the time when the flood is to commence. The second is the role that it may play in affecting the performance of the reservoir during the course of the flooding operation. In this paper the reservoir is assumed to be filled with only one fluid, so that there is no preferential segregation of reservoir fluids at the commencement of the flood. Moreover, the injected and in-place fluids are assumed to have the same characteristics, so that in effect we consider only a single-fluid problem.
