US4044833A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Acid foam fracturing
Assignee: Phillips Petroleum Co
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Filing: 1976-06-08
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Granted: 1977-08-30
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Expires: 1996-06-08
Abstract
Abstract Subterranean formations are fractured by means of an acid foam which can contain propping materials.
Inventors
- 👤 Herbert A. Volz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 04:42
CPC Classifications
E; E21; E21B; E21B43/00; E21B43/25; E21B43/26; E21B43/267; C; C09; C09K; C09K8/00; C09K8/60; C09K8/62; C09K8/70; C09K8/703; C09K8/72
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
140 words
A method for fracturing subterranean formations comprising the steps of: a. forming a gelled acid-liquid solution by combining an acid chemically reactive with a subterranean formation with about 250 to about 15,000 ppm of a gelling agent selected from carboxymethylcellulose polymers, polyacrylamides, and polysaccharides, b. adding a sufficient amount of a surfactant to said gelled acid-liquid solution obtained in (a) to form a stable foam at formation injection conditions, said surfactant being compatible with the other ingredients of the gelled acid-liquid solution and capable of producing foam in an acidic environment, c. introducing said gelled acid-liquid solution containing surfactant and an inert gas into a subterranean formation under sufficient pressure to form a foam and cause fracturing of said subterranean formation, and d. allowing the acid contained in said foam to react with the subterranean formation and cause etching thereof.
Claim 2
Independent Claim
140 words
A method for fracturing subterranean formations comprising the steps of: a. forming a gelled acid-liquid solution by combining an acid chemically reactive with a subterranean formation with about 250 to about 15,000 ppm of a gelling agent selected from carboxymethylcellulose polymers, polyacrylamides, and polysaccharides, b. adding a sufficient amount of a surfactant to said gelled acid-liquid solution obtained in (a) to form a stable foam at formation injection conditions, said surfactant being compatible with the other ingredients of the gelled acid-liquid solution and capable of producing foam in an acidic environment, c. introducing said gelled acid-liquid solution containing surfactant and an inert gas into a subterranean formation under sufficient pressure to form a foam and cause fracturing of said subterranean formation, and d. allowing the acid contained in said foam to react with the subterranean formation and cause etching thereof.
Claim 3
Dependent Claim
23 words
A method according to claim 1 further comprising the step of incorporating a propping agent uniformly throughout said gelled acid-liquid solution of (b).
Claim 4
Dependent Claim
36 words
A method according to claim 2 wherein said acid is selected from the group consisting of mineral acids and water soluble organic acids; said surfactant is an anionic foaming agent; and said propping agent is sand.
Claim 5
Dependent Claim
66 words
A method according to claim 1 said acid is selected from the group consisting of hydrochloric, hydrofluoric, phosphoric, sulfuric, sufamic and nitric acid; said liquid is water; said surfactant is selected from the group consisting of Igepal DM 970, Orvus K, Cor 180 and GAFAC; and said gas is selected from the group consisting of nitrogen, carbon dioxide, air, hydrocarbon gases, argon, helium, krypton and xenon.
Claim 6
Dependent Claim
31 words
A method according to claim 1 wherein said gelling agent is sodium carboxymethylcellulose and the concentration of sodium carboxymethylcellulose is in the range between about 350 ppm and about 10,000 ppm.
Claim 7
Dependent Claim
80 words
A method according to claim 1 wherein said acid is hydrochloric acid comprising from about 5 to about 50 percent by weight of the solution; said surfactant is selected from the group consisting of Igepal DM 970, Orvus K, Cor 180 and GAFAC and constitutes 0.5 to about 3 percent of the weight of the solution formed in step (b); said gas is nitrogen; said liquid is water; and said foam contains between 50 and 95 percent nitrogen by volume.
Claim 8
Dependent Claim
27 words
A method according to claim 6 wherein said surfactant is Igepal DM 970 and it constitutes 1.5% of the weight of the solution formed in step (b).
Claim 9
Dependent Claim
27 words
A method according to claim 6 wherein said surfactant is Orvus K and it constitutes 3 percent of the weight of the solution formed in step (b).
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) | 1980-08-29 | 1981-02-28 | 1981-08-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-08-29 | 1985-02-28 | 1985-08-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-08-29 | 1989-02-28 | 1989-08-30 | $7700.00 | Window Closed / Lapsed |