Abstract: A method of improving the sweep efficiency and increasing oil recovery of miscible flooding without reducing injectivity of the injection wells. Two sets of wells are used with one set being drilled between the other sets. The interwell area of a reservoir is pretreated by injecting a permeability-reducing agent (preferably a polymer) through said first set of wells. The polymer enters the more permeable zones and partially plugs them, both near and away from the wellbore. Thereafter, the injection or first set of wells are converted to producing wells. After the step of reducing the permeability contrast of the heterogeneous reservoirs, a miscible slug, that may or may not be preceded by a controlled salinity preflush, is injected into the second set of wells. There is no reduction in injectivity of the miscible injection wells, becuse no permeability-reducing agent has been injected therethrough.