An oil-recovery technique or process in which a fluid, capable of mixing completely with the oil it contacts, is injected into an oil reservoir to increase recovery. Fluids miscible with the reservoir oil are introduced into the reservoir through an injection well to displace the oil from the pores of the reservoir and drive it to a production well. The miscible fluid is introduced into the injection well at a sufficiently high pressure to drive the body of fluid through the reservoir where it collects and drives the reservoir oil to the production well.