Patent US4766958A successfully refreshed from Google Patents.
US4766958A
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Method of recovering viscous oil from reservoirs with multiple horizontal zones
Assignee: Mobil Oil AS
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Filing: 1987-01-12
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Granted: 1988-08-30
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Expires: 2007-01-12
Abstract
Abstract There is disclosed a method of recovering viscous oil from a subterranean viscous oil-containing formation separated into at least one upper and at least one lower zone by a horizontal layer having lower vertical permeability than the rest of the reservoir. The method comprises injecting steam into the lower zone until steam breakthrough occurs at the production well; subsequently injecting steam into both the upper and the lower zones; and, continuing to inject steam into both zones and recovering fluids, including oil from the production well.
Inventors
- 👤 David C. Faecke
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 09:42
CPC Classifications
E; E21; E21B; E21B43/00; E21B43/16; E21B43/24; E21B43/162
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
114 words
A method of recovering viscous oil from a viscous oil-containing formation separated, by at least one horizontal layer having vertical permeability of at least about 1 md, into at least one upper zone and at least one lower zone, the formation being penetrated by at least one injection well and at least one spaced-apart production well, comprising the consecutive steps of: (1) injecting through the injection well steam only into the lower zone until steam breakthrough occurs at the production well; (2) thereafter injecting steam into both, the upper and the lower zones; and (3) continuously injecting steam into the upper and the lower zones and recovering fluids, including oil, from the production well.
Claim 2
Independent Claim
114 words
A method of recovering viscous oil from a viscous oil-containing formation separated, by at least one horizontal layer having vertical permeability of at least about 1 md, into at least one upper zone and at least one lower zone, the formation being penetrated by at least one injection well and at least one spaced-apart production well, comprising the consecutive steps of: (1) injecting through the injection well steam only into the lower zone until steam breakthrough occurs at the production well; (2) thereafter injecting steam into both, the upper and the lower zones; and (3) continuously injecting steam into the upper and the lower zones and recovering fluids, including oil, from the production well.
Claim 3
Dependent Claim
19 words
A method of claim 1 wherein the horizontal layer has the vertical permeability of at least about 5 md.
Claim 4
Dependent Claim
19 words
A method of claim 2 wherein the horizontal layer has the vertical permeability of at least about 25 md.
Claim 5
Dependent Claim
41 words
A method of claim 3 wherein the steam is injected in said step (1) at the rate of about 1 to about 2 barrels per day, of cold water equivalent, per acre-foot of the portion of the formation permeable to steam.
Claim 6
Dependent Claim
41 words
A method of claim 4 wherein the steam is injected in said step (2) at the rate of about 1 to about 2 barrels per day, of cold water equivalent, per acre-foot of the portion of the formation permeable to steam.
Claim 7
Dependent Claim
28 words
A method of claim 5 wherein the steam has the temperature of about 475° F. to about 700° F. and a quality of about 50 to about 90%.
Claim 8
Dependent Claim
27 words
A method of claim 6 wherein the steam has the temperature of about 475° F. to about 550° F. and a quality of about 50 to 65%.
Claim 9
Dependent Claim
29 words
A method of claim 7 wherein the viscous oil has an API gravity of about 25° or less and a viscosity greater than about 20 centipoise at reservoir conditions.
Claim 10
Dependent Claim
19 words
A method of claim 8 wherein in said step (1) said steam breakthrough occurs only in the upper zone.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-08-30 | 1992-02-29 | 1992-08-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-08-30 | 1996-02-29 | 1996-08-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-08-30 | 2000-02-29 | 2000-08-30 | $7700.00 | Window Closed / Lapsed |