US3923666A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and composition for acidizing and fracturing wells
Assignee: Halliburton Co
•
Filing: 1973-02-26
•
Granted: 1975-12-02
•
Expires: 1993-02-26
Abstract
Abstract A method of acidizing or fracturing subterranean formations comprising injecting into the formation, a composition consisting essentially of a stable acidic gel made by the process of adding from about 25 to about 150 pounds of a linear polyacrylamide having a molecular weight of from about 1 to about 50 million to each 1000 gallons of an aqueous hydrochloric acid solution containing from about 25 to about 35 weight percent of hydrochloric acid. In another method of practicing the invention, the viscosity of the gelled acid is increased prior to injection into the formation by adding to the gel, an aldehyde compound soluble in aqueous solutions. An amount of the aldehyde equivalent to from about 0.01 to about 1.5 weight percent of aldehyde (based on the weight of hydrochloric acid used) is employed. Where this method of practicing the invention is used, the starting acid solution may have a concentration as low as 1 weight percent.
Inventors
- 👤 Walter R Dill
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 12:30
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/60; C09K8/62; C09K8/72; C09K8/74; C09K8/76; C08; C08K; C08K3/00; C08K3/16; C08K5/00; C08K5/04; C08K5/07; C09K8/84; C09K8/86; C09K8/88; C09K8/882; Y; Y10; Y10S; Y10S507/00; Y10S507/922; Y10S507/933
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
95 words
A METHOD FOR PREPARING A GELLED ACID USEFUL FOR ACIDIZING OR FRACTURING SUBTERRANEAN EARTH FORMATIONS, WHICH COMPRISES MIXING A WATER SOLUBLE, LINEAR POLYACRYLAMIDE HAVING A MOLECULAR WEIGHT IN THE RANGE OF ABOUT 1 TO ABOUT 50 MILLION, AN AQUEOUS HYDROCHLORIC ACID SOLUTION CONTAINING AN AMOUNT OF HYDROCHLORIC ACID EFFECTIVE TO PRODUCE A SUBSTANTIALLY HOMOGENEOUS GEL, AND AN ALDEHYDE COMPOUND SOLUBLE IN AQUEOUS SOLUTIONS; WHEREIN THE MIXING RATIO OF SAID POLYACRYLAMIDE TO SAID ACID SOLUTION IS IN THE RANGE OF ABOUT 25 TO ABOUT 150 POUNDS OF SAID POLYACRYLAMIDE PER 1,000 GALLONS OF SAID ACID SOLUTION.
Claim 2
Independent Claim
95 words
A METHOD FOR PREPARING A GELLED ACID USEFUL FOR ACIDIZING OR FRACTURING SUBTERRANEAN EARTH FORMATIONS, WHICH COMPRISES MIXING A WATER SOLUBLE, LINEAR POLYACRYLAMIDE HAVING A MOLECULAR WEIGHT IN THE RANGE OF ABOUT 1 TO ABOUT 50 MILLION, AN AQUEOUS HYDROCHLORIC ACID SOLUTION CONTAINING AN AMOUNT OF HYDROCHLORIC ACID EFFECTIVE TO PRODUCE A SUBSTANTIALLY HOMOGENEOUS GEL, AND AN ALDEHYDE COMPOUND SOLUBLE IN AQUEOUS SOLUTIONS; WHEREIN THE MIXING RATIO OF SAID POLYACRYLAMIDE TO SAID ACID SOLUTION IS IN THE RANGE OF ABOUT 25 TO ABOUT 150 POUNDS OF SAID POLYACRYLAMIDE PER 1,000 GALLONS OF SAID ACID SOLUTION.
Claim 3
Dependent Claim
20 words
The method defined in claim 1 wherein said aqueous hydrochloric acid solution contains at least 1 weight percent hydrochloric acid.
Claim 4
Dependent Claim
46 words
The method defined in claim 2 wherein said aldehyde compound contains from 1 to about 10 carbon atoms, and from about 0.01 weight percent to about 1.5 weight percent of said aldehyde compound is utilized, based upon the weight of hydrochloric acid in the acid solution.
Claim 5
Dependent Claim
12 words
The method defined in claim 2 wherein said aldehyde compound is formaldehyde.
Claim 6
Dependent Claim
28 words
The method defined in claim 2 wherein said aldehyde compound is paraformaldehyde whereby the rate at which a high viscosity acid gel product is developed is substantially decreased.
Claim 7
Dependent Claim
43 words
The method defined in claim 3 wherein about 0.35 weight percent of said aldehyde compound is utilized, based upon the weight of hydrochloric acid in the acid solution, and less than 50 pounds of polyacrylamide are mixed with the acid solution and aldehyde.
Claim 8
Dependent Claim
46 words
The method defined in claim 2 wherein the polyacrylamide and acid are first mixed with each other, and the aldehyde compound is then added to the polymer-acid reaction mixture after a period of time sufficient for substantially complete hydration of the polymer by the acid solution.
Claim 9
Dependent Claim
34 words
The method defined in claim 2 wherein the acid solution contains less than about 25 weight percent hydrochloric acid, and said aldehyde is mixed with said acid solution before said polyacrylamide is mixed therewith.
Claim 10
Dependent Claim
67 words
The method defined in claim 3 wherein said acid solution contains at least 30 weight percent hydrochloric acid, the aldehyde utilized is propionaldehyde, and said method is further characterized in including the step of subjecting said mixture to a temperature of at least 130*F immediately after the polymer, acid solution and propionaldehyde are mixed, whereby a high viscosity acid gel is developed at a very rapid rate.
Claim 11
Dependent Claim
35 words
The method defined in claim 3 wherein said mixing is carried out at a temperature of less than 100*F whereby the development of said gel and its rate of attainment of maximum viscosity are retarded.
Claim 12
Dependent Claim
28 words
The method defined in claim 3 wherein said aldehyde compound is paraformaldehyde whereby the rate of attainment of the maximum viscosity of the final gel product is retarded.
Claim 13
Independent Claim
144 words
THE METHOD OF TREATING A PERMEABLE, SUBTERRANEAN FORMATION TO ENHANCE THE PRODUCTIVITY OF HYDROCARBONS THEREFROM WHICH COMPRISES: MIXING FROM ABOUT 25 TO ABOUT 150 POUNDS OF A WATER SOLUBLE LINEAR POLYACRYLAMIDE HAVING A MOLECULAR WEIGHT OF FROM ABOUT 1 TO ABOUT 50 MILLION WITH EACH 1,000 GALLONS OF A COMPOSITION CONSISTING ESSENTIALLY OF AN AQUEOUS HYDROCHLORIC ACID SOLUTION CONTAINING AT LEAST 25 WEIGHT PERCENT HYDROCHLORIC ACID TO DEVELOP A STABLE, PUMPABLE ACID GEL; INJECTING SAID STABLE, PUMPABLE ACID GEL INTO THE INTERSTICES OF SAID PERMEABLE, SUBTERRANEAN FORMATION; THEN INJECTING AN EFFECTIVE AMOUNT OF AN ALDEHYDE COMPOUND SOLUBLE IN AQUEOUS SOLUTIONS INTO THE INTERSTICES OF THE PERMEABLE FORMATION TO MIX THE ALDEHYDE WITH THE PUMPABLE ACID GEL IN SITU, AND THEREBY INCREASE THE VISCOSITY OF THE GEL PRESENT IN THE FORMATION INTERSTICES BY IN SITU REACTION OF THE ALDEHYDE COMPOUND WITH THE PUMPABLE ACID GEL.
Claim 14
Independent Claim
144 words
THE METHOD OF TREATING A PERMEABLE, SUBTERRANEAN FORMATION TO ENHANCE THE PRODUCTIVITY OF HYDROCARBONS THEREFROM WHICH COMPRISES: MIXING FROM ABOUT 25 TO ABOUT 150 POUNDS OF A WATER SOLUBLE LINEAR POLYACRYLAMIDE HAVING A MOLECULAR WEIGHT OF FROM ABOUT 1 TO ABOUT 50 MILLION WITH EACH 1,000 GALLONS OF A COMPOSITION CONSISTING ESSENTIALLY OF AN AQUEOUS HYDROCHLORIC ACID SOLUTION CONTAINING AT LEAST 25 WEIGHT PERCENT HYDROCHLORIC ACID TO DEVELOP A STABLE, PUMPABLE ACID GEL; INJECTING SAID STABLE, PUMPABLE ACID GEL INTO THE INTERSTICES OF SAID PERMEABLE, SUBTERRANEAN FORMATION; THEN INJECTING AN EFFECTIVE AMOUNT OF AN ALDEHYDE COMPOUND SOLUBLE IN AQUEOUS SOLUTIONS INTO THE INTERSTICES OF THE PERMEABLE FORMATION TO MIX THE ALDEHYDE WITH THE PUMPABLE ACID GEL IN SITU, AND THEREBY INCREASE THE VISCOSITY OF THE GEL PRESENT IN THE FORMATION INTERSTICES BY IN SITU REACTION OF THE ALDEHYDE COMPOUND WITH THE PUMPABLE ACID GEL.
Claim 15
Dependent Claim
39 words
The method defined in claim 12 wherein the aldehyde compound utilized is formaldehyde, and the quantity injected is at least 0.1 weight percent, based upon the total weight of acid in the pumpable acid gel injected into the formation.
Claim 16
Dependent Claim
61 words
The method defined in claim 12 and further characterized as including the steps of: measuring the temperature of the formation at the location where said pumpable acid gel is injected thereinto; and selecting the amount and type of said aldehyde compound for injection to develop, in situ, a high viscosity gel breaking after a desired time interval at said measured temperature.
Claim 17
Dependent Claim
89 words
A HIGH VISCOSITY ACIDIC GEL COMPOSITION USEFUL IN FRACTURING, ACIDIZING AND PROPPING OPERATIONS IN THE PRODUCTION OF HYDROCARBONS FROM SUBTERRANEAN FORMATIONS CONSISTING ESSENTIALLY OF A METHYLOL HYDROCHLORIDE SALT OF A LINEAR POLYACRYLAMIDE HAVING A MOLECULAR WEIGHT EXCEEDING 1 MILLION AND PRODUCED BY REACTING A WATER SOLUBLE LINEAR POLYACRYLAMIDE HAVING A MOLECULAR WEIGHT OF FROM ABOUT 1 TO ABOUT 50 MILLION WITH HYDROCHLORIC ACID IN AN AQUEOUS ENVIRONMENT TO YIELD A HYDROCHLORIDE SALT OF SAID LINEAR POLYACRYLAMIDE, THEN, REACTING AN ALDEHYDE COMPOUND SOLUBLE IN AQUEOUS SOLUTIONS WITH SAID HYDROCHLORIDE SALTS.
Claim 18
Dependent Claim
89 words
A HIGH VISCOSITY ACIDIC GEL COMPOSITION USEFUL IN FRACTURING, ACIDIZING AND PROPPING OPERATIONS IN THE PRODUCTION OF HYDROCARBONS FROM SUBTERRANEAN FORMATIONS CONSISTING ESSENTIALLY OF A METHYLOL HYDROCHLORIDE SALT OF A LINEAR POLYACRYLAMIDE HAVING A MOLECULAR WEIGHT EXCEEDING 1 MILLION AND PRODUCED BY REACTING A WATER SOLUBLE LINEAR POLYACRYLAMIDE HAVING A MOLECULAR WEIGHT OF FROM ABOUT 1 TO ABOUT 50 MILLION WITH HYDROCHLORIC ACID IN AN AQUEOUS ENVIRONMENT TO YIELD A HYDROCHLORIDE SALT OF SAID LINEAR POLYACRYLAMIDE, THEN, REACTING AN ALDEHYDE COMPOUND SOLUBLE IN AQUEOUS SOLUTIONS WITH SAID HYDROCHLORIDE SALTS.
Claim 19
Dependent Claim
27 words
A high viscosity acidic gel composition as defined in claim 15 wherein said linear polyacrylamide has a molecular weight of from about 3 to about 6 million.
Claim 20
Dependent Claim
27 words
A high viscosity acidic gel as defined in claim 15 wherein said aldehyde compound is selected from the group consisting of formaldehyde, paraformaldehyde, propionaldehyde, aldol, and glutaraldehyde.
Claim 21
Dependent Claim
24 words
A high viscosity acidic gel composition as defined in claim 15 wherein said gel composition has a viscosity of at least 100, 000 centipoises.
Claim 22
Dependent Claim
47 words
A high viscosity acidic gel composition as defined in claim 15 wherein said reaction of linear polyacrylamide with hydrochloric acid is carried out by mixing from 25 to 150 pounds of the polyacrylamide with an aqueous hydrochloric acid solution containing at least 15 weight percent hydrochloric acid.
Claim 23
Dependent Claim
17 words
A high viscosity acidic gel composition as defined in claim 17 wherein said aldehyde compound is formaldehyde.
References Cited (Backward Citations)
US3122204A
Cited
US3179171A
Cited
US3252904A
Cited
US3434971A
Cited
US3442803A
Cited
US3500929A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-12-01 | 1979-06-02 | 1979-12-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-01 | 1983-06-02 | 1983-12-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-01 | 1987-06-02 | 1987-12-02 | $7700.00 | Window Closed / Lapsed |