US4846276A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Water-alternating-gas flooding of a hydrocarbon-bearing formation
Assignee: Marathon Oil Co
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Filing: 1988-09-02
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Granted: 1989-07-11
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Expires: 2008-09-02
Abstract
Abstract A zone of a subterranean formation containing a low-viscosity crude oil which has already been waterflooded to completion is sequentially flooded with alternating slugs of produced gas and water to produce incremental amounts of the oil. The zone is characterized as a low-permeability zone having mixed geology, i.e., containing two or more rocks of differing permeability randomly distributed throughout the zone.
Inventors
- 👤 Hiemi K. Haines
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 20:15
CPC Classifications
E; E21; E21B; E21B43/00; E21B43/16; E21B43/20
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
166 words
An oil recovery process for recovering a low viscosity crude oil from an oil-bearing zone of a subterranean formation comprising: (a) injecting a gas into said oil-bearing zone of said subterranean formation via an injection well in fluid communication with said oilbearing zone, said gas injected at an injection pressure substantially below the minimum miscibility pressure of said gas in said low-viscosity crude oil; (b) displacing said low-viscosity crude oil away from said injection well toward an oil production well in fluid communication with said oil-bearing formation; (c) continuously recovering said low-viscosity crude oil from said oil production well; (d) thereafter terminating said injection of said gas upon substantial diminution of said continuous crude oil recovery from said production well; (e) injecting water into said oil-bearing zone of said formation via said injection well; (f) displacing said low-viscosity crude oil away from said injection well toward said oil production well; (g) recovering said low-viscosity oil from said oil production well; and (h) terminating said water injection.
Claim 2
Dependent Claim
166 words
An oil recovery process for recovering a low viscosity crude oil from an oil-bearing zone of a subterranean formation comprising: (a) injecting a gas into said oil-bearing zone of said subterranean formation via an injection well in fluid communication with said oilbearing zone, said gas injected at an injection pressure substantially below the minimum miscibility pressure of said gas in said low-viscosity crude oil; (b) displacing said low-viscosity crude oil away from said injection well toward an oil production well in fluid communication with said oil-bearing formation; (c) continuously recovering said low-viscosity crude oil from said oil production well; (d) thereafter terminating said injection of said gas upon substantial diminution of said continuous crude oil recovery from said production well; (e) injecting water into said oil-bearing zone of said formation via said injection well; (f) displacing said low-viscosity crude oil away from said injection well toward said oil production well; (g) recovering said low-viscosity oil from said oil production well; and (h) terminating said water injection.
Claim 3
Dependent Claim
14 words
The process of claim 1 further comprising repeating steps (a) through (h) in sequence.
Claim 4
Dependent Claim
25 words
The process of claim 1 wherein the viscosity of said low viscosity crude oil is between about 0.5 and about 5 centipoise at formation conditions.
Claim 5
Dependent Claim
24 words
The process of claim 1 wherein the API gravity of said low viscosity crude oil is greater than about 40° API at formation conditions.
Claim 6
Dependent Claim
27 words
The process of claim 1 wherein said formation has been waterflooded to completion prior to injecting said gas and said process is a tertiary oil recovery process.
Claim 7
Dependent Claim
23 words
The process of claim 5 wherein the percentage of incremental oil recovery in steps (c) and (g) is greater than about 10 percent.
Claim 8
Dependent Claim
18 words
The process of claim 1 further comprising producing said gas from a subterranean formation prior to step a).
Claim 9
Dependent Claim
26 words
The process of claim 7 wherein said subterranean formation from which said gas is produced is a different formation than said formation containing said oil-bearing zone.
Claim 10
Dependent Claim
26 words
The process of claim 7 wherein said subterranean formation from which said gas is produced is the same formation as said formation containing said oil-bearing zone.
Claim 11
Dependent Claim
21 words
The process of claim 1 wherein said oil-bearing zone has an average permeability of between about 25 and about 1000 millidarcies.
Claim 12
Dependent Claim
19 words
The process of claim 1 wherein said oil-bearing zone contains two or more types of rock of differing permeability.
Claim 13
Dependent Claim
12 words
The process of claim 11 wherein said oil-bearing zone comprises a conglomerate.
Claim 14
Dependent Claim
24 words
The process of claim 1 wherein said injection pressure of said gas is substantially above the bubble point pressure of said low-viscosity crude oil.
Claim 15
Dependent Claim
26 words
The process of claim 1 wherein said water injection is terminated after substantial diminution of said crude oil recovery in step g) from said production well.
Claim 16
Dependent Claim
40 words
The process of claim 1 wherein said gas contacts said low viscosity crude oil in said oil-bearing zone of said subterranean formation, at a temperature and pressure sufficient to substantially swell and reduce the viscosity of said low-viscosity crude oil.
References Cited (Backward Citations)
US1658305A
Cited
US2609051A
Cited
US3134433A
Cited
US3244228A
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US3227210A
Cited
US3344857A
Cited
US3493049A
Cited
US3525396A
Cited
US3525395A
Cited
US3882940A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-07-10 | 1993-01-09 | 1993-07-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-07-10 | 1997-01-09 | 1997-07-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-07-10 | 2001-01-09 | 2001-07-11 | $7700.00 | Window Closed / Lapsed |