US3575240A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Recovery of heavy oils by fracturing and injection of gas
Assignee: Cities Service Oil Co
•
Filing: 1969-04-25
•
Granted: 1971-04-20
•
Expires: 1989-04-25
Abstract
Abstract High-viscosity oil is recovered from subterranean reservoirs by a cyclic process that alternately enhances the mobility of the heavy oil at increasing distances from the production well and recovers the more mobile oil that drains into the vicinity of the production well. The increased mobility of the oil is achieved by the cyclic injection of a gas having a relatively high oil solubility into the reservoir through, and alternately producing the swollen oil from, the production well. The area of the formation contacted by the injection gas is greatly increased by fracturing the oil-bearing formation prior to gas injection. The fracture permits the injected gas to be carried into those areas of the formation not otherwise in immediate communication with the well and enhances the withdrawal of oil by providing a convenient path for the swollen oil to flow through in the formation to the production well.
Inventors
- 👤 Vaughan W Rhoades
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 22:31
CPC Classifications
E; E21; E21B; E21B43/00; E21B43/16; E21B43/18; E21B43/164
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
17 words
The method of claim 1 in which the fracturing is accomplished by hydraulic fracturing of the formation.
Claim 2
Dependent Claim
17 words
The method of claim 1 in which the fracturing is accomplished by explosive fracturing of the formation.
Claim 3
Dependent Claim
25 words
The method of claim 1 in which the highly soluble gas is selected from the group consisting of ethane and carbon dioxide and mixtures thereof.
Claim 4
Dependent Claim
18 words
The method of claim 1 in which the viscosity of the oil is at least about 25 centiposes.
Claim 5
Dependent Claim
12 words
The method of claim 1 in which the injected gas comprises ethane.
Claim 6
Dependent Claim
19 words
The method of claim 6 in which the reservoir temperature is from about 75* F. to about 100* F.
Claim 7
Dependent Claim
31 words
The method of claim 7 in which the injection pressure is in the range of from at least the vapor pressure of ethane at the reservoir temperature to about 750 p.s.i.a.
Claim 8
Dependent Claim
13 words
The method of claim 1 in which the injected gas comprises carbon dioxide.
Claim 9
Dependent Claim
19 words
The method of claim 9 in which the reservoir temperature is from about 75* F. to about 100* F.
Claim 10
Dependent Claim
32 words
The method of claim 10 in which the injection pressure is in the range of from at least the vapor pressure of carbon dioxide at the reservoir temperature to about 1,100 p.s.i.a.
Claim 11
Dependent Claim
63 words
The method of claim 1 in which said cyclic operation is continued until the cumulative solution gas/oil ratio of the fluids produced increases rapidly due to the decreased efficiency of gas-oil contact as depletion of the thus-contacted oil continues and the decreased ability of the thus-contacted oil to drain through the reservoir, including the fracture therein, to the immediate vicinity of the well.
Claim 12
Dependent Claim
112 words
The method of claim 1 and including the injection of the solution gas recovered from the original well during said withdrawing steps into the reservoir through an offset well so as to saturate oil in the vicinity of said offset well at the injection pressure and thereafter withdrawing the thus-saturated oil from the reservoir through the offset well, and injecting the solution gas recovered from said offset well back into the formation through said original well to saturate additional quantities of oil, whereby the solution gas may be continuously utilized for the swelling of additional quantities of heavy oil as opposed to its inherently cyclic use with respect to a single well.
Claim 13
Dependent Claim
33 words
The method of claim 13 in which said cyclic combined operation between said original well and said offset well is continued until the cumulative solution gas/oil ratio from said combined operation increases rapidly.
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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) | 1974-04-19 | 1974-10-19 | 1975-04-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-04-19 | 1978-10-19 | 1979-04-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-04-19 | 1982-10-19 | 1983-04-20 | $7700.00 | Window Closed / Lapsed |