US 2012/0267097 A1 · MULTI-STEP SOLVENT EXTRACTION PROCESS FOR HEAVY OIL RESERVOIRS

Abstract

There is disclosed a multi-step in situ extraction process for heavy oil reservoirs using a solvent having various steps, including, removing, from areas in contact with said heavy oil, solvent blockers to create voids and to increase an interfacial area of unextracted heavy oil contactable by said solvent and injecting solvent in vapour form into the voids to raise the reservoir pressure until sufficient solvent is present in a liquid form to fill the voids and to contact said increased interfacial area of said heavy oil. Next the reservoir is shut in for a period of time to permit said solvent to diffuse into said unextracted oil across said interfacial area from the solvent filled voids in a ripening step to create a reduced viscosity blend of solvent and oil and one or more reservoir characteristics is measured to confirm the extent of solvent dilution that has occurred of the unextracted oil in the reservoir. Then gravity drainage based production is started from the reservoir once the blend has a viscosity low enough to permit the blend to drain through said reservoir to a production well.

Claims19

Dependent claims

A multi-step in situ extraction process for heavy oil reservoirs, said process using a solvent and comprising the steps of:

a. Removing liquids and gases from areas in contact with said heavy oils to increase an interfacial area of unextracted heavy oil contactable by said solvent;
b. Injecting said solvent in vapour form into said areas to raise the reservoir pressure until sufficient solvent is present in a liquid form to contact said increased interfacial area of said heavy oil;
c. Shutting in said reservoir for a sufficient period of time to permit said solvent to diffuse into said unextracted oil across said interfacial area in a ripening step to create a reduced viscosity blend of solvent and oil;
d. Measuring one or more reservoir characteristics to confirm the extent of solvent dilution that has occurred of the unextracted oil in the reservoir, and
e. Commencing gravity drainage based production from said reservoir upon said blend having a viscosity low enough to permit said blend to drain through said reservoir to a production well.

2 more elements

Dependencies are inferred from the claim text.

Multi-step solvent extraction process for heavy oil reservoirs

Life of this patent

Multi-step solvent extraction process for heavy oil reservoirs

Life of this patent

Abstract

Claims19