Recovery of oil from reservoirs
In this secondary recovery method substantially all the oil in a formation may be displaced by a less valuable fluid. A liquid solvent is first injected into an injection well under a pressure above the vapor pressure of the solvent. After a time this solvent forms with the reservoir oil an oil-solvent transition zone in which the composition of the components varies from 100% oil at the leading edge to 100% solvent at the trailing edge. The thickness of this zone stabilizes within a few feet of the input well and does not vary as the solvent progresses through the reservoir from the input well to the producing well. After a calculated amount of solvent has been injected, a scavenging fluid is introduced into the reservoir through the same input wells, displacing the oil-solvent transition zone and the pure solvent zone back into the reservoir. (16 claims)
- Assignee:
- Pan American Petr Corp.
- Patent Number(s):
- US 3354953
- OSTI ID:
- 6284193
- Country of Publication:
- United States
- Language:
- English
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