A method for the miscible displacement of petroleum from a subterranean reservoir is provided. The method involves injecting two miscible fluids into an injection well and producing petroleum from a production well. A first solvent, more dense than water, is injected into the reservoir near the top of the reservoir, and a second solvent, less dense than water, is injected into the reservoir near or at the bottom of the reservoir. Both solvents are followed by water. The first solvent will tend to flow downward and the second solvent will tend to rise. The solvents will blend and provide piston-like displacement through the reservoir.