EFFECT OF SOLVENT ON STEAM RECOVERY OF HEAVY OIL.

Solvents and light ends of crudes are frequently used as diluents to facilitate pumping and pipeline transportation of heavy crudes. The use of solvent alone for in-situ recovery of heavy oil tends to be limited because of its high cost; however, the use of solvent as an additive to steam processes has been tested both in the laboratory and in the field. The results of these tests are mixed. The authors use numerical experiments to delineate the recovery mechanism of a steam-slug process when solvents are present. A good understanding of the mechanism will help provide an interpretation of the conditions under which solvents can improve steam oil recovery. The study focuses on the use of small quantities of solvent - i. e. , no more than 10% of the steam volume.