US3799266A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fracturing method using acid external emulsions
Assignee: ExxonMobil Upstream Research Co
•
Filing: 1972-08-18
•
Granted: 1974-03-26
•
Expires: 1992-08-18
Abstract
Abstract A subterranean carbonate formation is treated by injecting into the formation an emulsion comprising an aqueous acid solution as the external phase and a hydrocarbon oil as the internal phase. The external acid phase constitutes at least 20 volume percent of the emulsion and preferably between 20 and 50 volume percent of the emulsion.
Inventors
- 👤 O Kiel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 04:53
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/60; C09K8/62; C09K8/64; C09K8/72; Y; Y10; Y10S; Y10S507/00; Y10S507/933
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
12 words
A method as defined in claim 1 wherein said acid is HCl.
Claim 2
Dependent Claim
21 words
A method as defined in claim 2 wherein said aqueous solution contains from 15 weight percent to 37 weight percent HCl.
Claim 3
Dependent Claim
46 words
A method as defined in claim 1 wherein said aqueous acid solution contains a sufficient amount of a polymeric thickening agent to impart an apparent viscosity to said aqueous solution of at least 10 centipoises at 70*F and a shear rate of about 511 reciprocal seconds.
Claim 4
Dependent Claim
48 words
A method as defined in claim 4 wherein the concentration of said hydrocarbon oil and said polymeric thickening agent in said emulsion is sufficient to provide the emulsion with an apparent viscosity of at least 100 centipoises at 70*F and a shear rate of about 511 reciprocal seconds.
Claim 5
Dependent Claim
15 words
A method as defined in claim 4 wherein said polmeric thickening agent is guar gum.
Claim 6
Dependent Claim
15 words
A method as defined in claim 4 wherein said polymeric thickening agent is a polyacrylamide.
Claim 7
Dependent Claim
30 words
A method as defined in claim 1 wherein said aqueous acid solution is injected in said formation at a rate and pressure sufficient to open a fracture in said formation.
Claim 8
Independent Claim
93 words
A method of acid fracturing a subterranean formation containing carbonate constituents which comprises injecting into said formation at a rate and pressure sufficient to open a fracture therein a first liquid, and thereafter injecting into said fracture an emulsion comprising a hydrocarbon oil as the internal phase and an aqueous solution containing at least 3 weight percent of an acid as the external phase, said aqueous acid solution constituting at least 20 volume percent of said emulsion and said emulsion having an apparent viscosity substantially less than the viscosity of said first liquid.
Claim 9
Dependent Claim
46 words
A method as defined in claim 9 wherein said aqueous acid solution contains a sufficient amount of a polymeric thickening agent to impart an apparent viscosity of at least 10 centipoises at 70*F and a shear rate of 511 reciprocal seconds to said aqueous acid solution.
Claim 10
Dependent Claim
24 words
A method as defined in claim 9 wherein the viscosity of said first liquid is at least five times the viscosity of said emulsion.
Claim 11
Independent Claim
79 words
A method of acid fracturing a subterranean formation surrounding a wellbore which comprises injecting into said formation at a rate and pressure sufficient to open a fracture in said formation an emulsion comprising an aqueous solution containing at least 3 weight percent of an acid as the external phase and a hydrocarbon oil as the internal phase, said aqueous solution comprising at least 20 volume percent of said emulsion; and thereafter injecting a concentrated acid solution into said fracture.
Claim 12
Dependent Claim
20 words
A method as defined in claim 12 wherein the concentrated acid solution comprises from 20 to 37 weight percent HCl.
Claim 13
Dependent Claim
24 words
A method as defined in claim 12 wherein said aqueous acid solution constitutes between about 20 and about 50 volume percent of said emulsion.
Claim 14
Dependent Claim
45 words
A method as defined in claim 12 wherein said aqueous acid solution contains sufficient amount of an acid thickening agent to impart an apparent viscosity of at least 10 centipoises at 70F and a shear rate of 511 reciprocal seconds to said aqueous acid solution.
Claim 15
Independent Claim
84 words
A method of acid fracturing a subterranean formation containing carbonate constituents which comprises injecting into said formation at a pressure and rate sufficient to open a fracture therein an emulsion comprising from about 20 to about 50 volume percent of an aqueous liquid containing at least 3 weight percent of an acid as the external phase, from about 50 to about 80 volume percent of a hydrocarbon oil as the internal phase, and an effective amount of a surface-active agent to stabilize the emulsion.
Claim 16
Dependent Claim
26 words
A method as defined in claim 16 wherein said emulsion further includes an acid thickening agent for imparting viscosity to the external phase of the emulsion.
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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) | 1977-03-25 | 1977-09-24 | 1978-03-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-25 | 1981-09-24 | 1982-03-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-25 | 1985-09-24 | 1986-03-26 | $7700.00 | Window Closed / Lapsed |