| 摘要 |
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. |
