| US 7,464,756 B2 | ||
| Process for in situ recovery of bitumen and heavy oil | ||
| Ian Donald Gates, Calgary (Canada); and Anthony Martin Harold Gutek, Calgary (Canada) | ||
| Assigned to Exxon Mobil Upstream Research Company, Houston, Tex. (US) | ||
| Filed on Feb. 04, 2005, as Appl. No. 11/50,965. | ||
| Claims priority of application No. 2462359 (CA), filed on Mar. 24, 2004. | ||
| Prior Publication US 2005/0211434 A1, Sep. 29, 2005 | ||
| Int. Cl. E21B 43/24 (2006.01) | ||
| U.S. Cl. 166—272.3 [166/263; 166/272.4; 166/401] | 17 Claims |
| 1. A method to recover heavy hydrocarbons from an underground reservoir, the underground reservoir being penetrated by an
injection well and a production well, the method comprising the steps of:
(a) injecting steam and a heavy hydrocarbon solvent into the injection well over time, while producing reservoir hydrocarbons
from the production well;
(b) transitioning from the steam and heavy hydrocarbon solvent injections to a lighter hydrocarbon solvent injection, while
continuing to produce hydrocarbons from the production well;
(c) continuing to inject the lighter hydrocarbon solvent while producing hydrocarbons from the production well; and
(d) enhancing the solubility of solvents in steps (a) through (c) by monitoring and adjusting reservoir pressure.
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