US3752233A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydrazine overflush treatment in hydraulic fracturing
Assignee: Marathon Oil Co
•
Filing: 1971-12-15
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Granted: 1973-08-14
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Expires: 1991-12-15
Abstract
Abstract Improved fracturing of subterranean reservoirs with fracturing fluids containing high molecular weight polymers, e.g., polyacrylamides, is obtained by first fracturing the formation with the fracturing fluid, and thereafter injecting 5-1,000 gallons per vertical foot of reservoir of an aqueous solution containing 0.005 percent to about 30 percent by volume of hydrazine. The hydrazine tends to increase permeability to the flow of reservoir fluids, the permeability having been reduced by the high molecular weight polymers in the fracturing fluid.
Inventors
- 👤 M Svaldi
- 👤 B Knight
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 23:32
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/60; C09K8/62
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
24 words
The process of claim 1 wherein the fracturing fluid is flushed from the wellbore before the aqueous hydrazine solution is injected into the reservoir.
Claim 2
Dependent Claim
26 words
The process of claim 1 wherein about 40 gallons to about 800 gallons of the aqueous hydrazine solution is injected per vertical foot of the reservoir.
Claim 3
Dependent Claim
25 words
The process of claim 1 wherein about 50 gallons to about 500 gallons of the aqueous hydrazine solution is injected per vertical foot of reservoir.
Claim 4
Dependent Claim
19 words
The process of claim 1 wherein the hydrazine concentration is about 0.0075 percent to about 5 percent by volume.
Claim 5
Dependent Claim
19 words
The process of claim 1 wherein about 0.01 percent to about 3 percent volume is the concentration of hydrazine.
Claim 6
Dependent Claim
17 words
The process of claim 1 wherein the fracturing fluid contains a partially hydrolyzed, high molecular weight polyacrylamide.
Claim 7
Dependent Claim
81 words
An improved process of fracturing a subterranean reservoir wherein an aqueous fracturing fluid comprised of a partially hydrolyzed, high molecular weight polyacrylamide is injected into a well bore in fluid communication with a reservoir at a pressure sufficient to fracture the formation, the improvement comprising injecting after the fracturing fluid about 5 gallons to about 1, 000 gallons of an aqueous hydrazine solution per vertical foot of reservoir, the hydrazine concentration being about 0.0075 percent to about 5 percent by volume.
Claim 8
Dependent Claim
19 words
The process of claim 8 wherein the hydrazine concentration is about 0.01 percent to about 3 percent by volume.
Claim 9
Dependent Claim
28 words
The process of claim 8 wherein about 40 gallons to about 800 gallons of the aqueous hydrazine solution per vertical foot of reservoir is injected into the reservoir.
Claim 10
Dependent Claim
25 words
The process of claim 8 wherein about 50 gallons to about 500 gallons of the aqueous hydrazine solution per vertical foot of reservoir is injected.
References Cited (Backward Citations)
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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) | 1976-08-13 | 1977-02-12 | 1977-08-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-13 | 1981-02-12 | 1981-08-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-13 | 1985-02-12 | 1985-08-14 | $7700.00 | Window Closed / Lapsed |