US3720265A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for stimulating well production
Assignee: Texaco Inc
•
Filing: 1971-06-21
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Granted: 1973-03-13
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Expires: 1991-06-21
Abstract
Abstract The production of hydrocarbons from a subterranean hydrocarbonbearing formation containing acid-soluble components, such as one composed at least in part of dolomite or limestone, is stimulated by injecting into the formation a composition comprising an aqueous solution of a mineral acid having dissolved therein a phosphate ester of prescribed formula. The elimination of plugging of capillary openings within the formation and mineral scale deposition on production equipment due to postprecipitation of dissolved salts subsequent to acidization by means of the said phosphate ester results in a substantial improvement in hydrocarbon recovery.
Inventors
- 👤 J Tate
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 17:24
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/60; C09K8/62; C09K8/72; C09K8/74; C09K8/78
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
185 words
A method of increasing the production of fluids from a subterranean fluid-bearing formation having present therein acid-soluble components comprising injecting down the well bore penetrating said formation and injecting therefrom into said formation under a pressure greater than the formation pressure, an aqueous solution containing from about 3 to 30 percent by weight of a mineral acid having dissolved therein from about 0.1 to 2.5 percent by weight of a phosphate ester having the general formula wherein R is either hydrogen or a C13H27O-(C2H40)n 1-C2H4 group in which n is 1 to 3, m is equal to 2 or 3 and R is a hydrogen atom not more than m minus 1 times, A is hydrogen or an alkali metal, or a mixture of said esters, said ester having a molecular weight in the range of from about 750 to about 1,730, maintaining said solution in contact with the formation and production equipment for a time sufficient for the acid to chemically react with the acid-soluble components of the formation to etch passageways therethrough thereby increasing substantially the flow capacity of the said subterranean formation.
Claim 2
Independent Claim
185 words
A method of increasing the production of fluids from a subterranean fluid-bearing formation having present therein acid-soluble components comprising injecting down the well bore penetrating said formation and injecting therefrom into said formation under a pressure greater than the formation pressure, an aqueous solution containing from about 3 to 30 percent by weight of a mineral acid having dissolved therein from about 0.1 to 2.5 percent by weight of a phosphate ester having the general formula wherein R is either hydrogen or a C13H27O-(C2H40)n 1-C2H4 group in which n is 1 to 3, m is equal to 2 or 3 and R is a hydrogen atom not more than m minus 1 times, A is hydrogen or an alkali metal, or a mixture of said esters, said ester having a molecular weight in the range of from about 750 to about 1,730, maintaining said solution in contact with the formation and production equipment for a time sufficient for the acid to chemically react with the acid-soluble components of the formation to etch passageways therethrough thereby increasing substantially the flow capacity of the said subterranean formation.
Claim 3
Dependent Claim
12 words
Method as claimed in claim 1 wherein said ester has the formula
Claim 4
Dependent Claim
12 words
Method as claimed in claim 1 wherein said ester has the formula
Claim 5
Dependent Claim
26 words
Method as claimed in claim 1 wherein said ester is present in the composition in an amount of from about 0.3 to 1.5 percent by weight.
Claim 6
Dependent Claim
18 words
Method as claimed in claim 1 wherein said ester is present in the form of the sodium salt.
Claim 7
Dependent Claim
12 words
Method as claimed in claim 1 wherein said acid is hydrochloric acid.
Claim 8
Dependent Claim
13 words
Method as claimed in claim 1 wherein the said acid is sulfuric acid.
Claim 9
Dependent Claim
26 words
Method as claimed in claim 1 wherein the said ester is dissolved in about 5 to about 20 percent by weight solution of the mineral acid.
Claim 10
Dependent Claim
48 words
Method as claimed in claim 1 wherein the said acid is about 5 to about 28 percent by weight hydrochloric acid and the said ester is present in an amount of from about 0.3 to about 1.5 percent by weight, based on the total weight of the composition.
Claim 11
Dependent Claim
14 words
Method as claimed in claim 1 wherein the said formation is a hydrocarbon-bearing formation.
Claim 12
Dependent Claim
36 words
Method as claimed in claim 1 wherein the said aqueous solution is injected down the well bore penetrating said formation under a pressure greater than the formation pressure and sufficient to create fractures in the formation.
Claim 13
Dependent Claim
40 words
Method as claimed in claim 1 wherein the said aqueous solution is injected down the well bore penetrating said formation under A pressure greater than the formation pressure but less than the pressure required to create fractures in the formation.
References Cited (Backward Citations)
US2802531A
Cited
US3233672A
Cited
US3319714A
Cited
US3348613A
Cited
US3429824A
Cited
US3488289A
Cited
US3502587A
Cited
US3483925A
Cited
US3656551A
Cited
US3630285A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-03-12 | 1976-09-11 | 1977-03-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-12 | 1980-09-11 | 1981-03-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-12 | 1984-09-11 | 1985-03-13 | $7700.00 | Window Closed / Lapsed |