Well-pattern investigation and selection by surfactant-polymer flooding performance in heterogeneous reservoir consisting of interbedded low-permeability layer

Surfactant-polymer (SP) flooding has been demonstrated to be one of the most efficient methods of recovering the residual oil in the enhanced oil recovery (EOR) stage. However, the uses of SP flooding in horizontal or vertical well patterns are still being disputed from either technical or economic points of view, particularly in complicated reservoir systems. We investigated the successful application of SP flooding for many well-pattern combinations in a heterogeneous reservoir. A quarter five-spot pattern reservoir model is proposed with three different permeable layers; in particular, the interbedded layer has a much lower permeability than the other layers. The combinations of horizontal injectors and producers possess the most successful EOR processes, especially when the wells are interchangeably located in the high-permeability layers. However, the short-length horizontal-well combination is more preferable than the full-length horizontal-well pattern from the results of a comprehensive evaluation.