US4151879A
Expired / Lapsed
US
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Method for acidizing a subterranean formation
Assignee: Schlumberger Technology Corp
•
Filing: 1977-08-15
•
Granted: 1979-05-01
•
Expires: 1997-08-15
Abstract
Abstract The permeability of a subterranean formation is increased by injecting into the formation, a conventional mud acidizing solution (HCl/HF) followed by a fluoboric acid solution. Use of fluoboric acid as an overflush is believed to deter clay migration and thereby significantly reduce or delay production decline which is often otherwise encountered shortly after conventional mud acidizing treatments.
Inventors
- 👤 Ronnie L. Thomas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 06:50
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/60; C09K8/62; C09K8/72
Claims Analysis
Total Claims: 49
Claim 1
Independent Claim
57 words
A method for increasing the permeability of a subterranean formation comprising injecting into said formation in sequence: (a) an aqueous mud acidizing solution; (b) a spacer fluid selected from the group consisting of an aqueous solution of an ammonium halide or a weak organic acid, liquid hydrocarbons, and alcohols; and (c) an aqueous solution of fluoboric acid.
Claim 2
Independent Claim
57 words
A method for increasing the permeability of a subterranean formation comprising injecting into said formation in sequence: (a) an aqueous mud acidizing solution; (b) a spacer fluid selected from the group consisting of an aqueous solution of an ammonium halide or a weak organic acid, liquid hydrocarbons, and alcohols; and (c) an aqueous solution of fluoboric acid.
Claim 3
Dependent Claim
47 words
The method of claim 1 wherein the mud acidizing solution contains from about 1 to about 37 weight percent HCl and from about 0.5 to about 25 weight percent HF, and wherein the concentration of the fluoboric acid is from about 1 to about 48 weight percent.
Claim 4
Dependent Claim
47 words
The method of claim 2 wherein the mud acidizing solution contains from about 3 to about 25 weight percent HCl and from about 1 to about 10 weight percent HF, and wherein the concentration of the fluoboric acid is from about 2 to about 20 weight percent.
Claim 5
Dependent Claim
21 words
The method of claim 3 wherein the spacer is an aqueous solution of an ammonium halide or a weak organic acid.
Claim 6
Independent Claim
93 words
A method for stimulating a siliceous clay containing formation to increase the production of fluids therefrom, wherein said formation is of the type which exhibits an initial production increase following a conventional mud acidizing treatment but which suffers a rapid production decline thereafter, which comprises injecting into said formation in sequence: (a) an aqueous mud acidizing solution; and (b) an aqueous solution consisting substantially of fluoboric acid, so that the permeability of said formation is increased and so that fines are stabilized within said formation, thereby permitting a prolonged period of increased production.
Claim 7
Independent Claim
93 words
A method for stimulating a siliceous clay containing formation to increase the production of fluids therefrom, wherein said formation is of the type which exhibits an initial production increase following a conventional mud acidizing treatment but which suffers a rapid production decline thereafter, which comprises injecting into said formation in sequence: (a) an aqueous mud acidizing solution; and (b) an aqueous solution consisting substantially of fluoboric acid, so that the permeability of said formation is increased and so that fines are stabilized within said formation, thereby permitting a prolonged period of increased production.
Claim 8
Dependent Claim
47 words
The method of claim 5 wherein the mud acidizing solution contains from about 1 to about 37 weight percent HCl and from about 0.5 to about 25 weight percent HF, and wherein the concentration of the fluoboric acid is from about 1 to about 48 weight percent.
Claim 9
Dependent Claim
47 words
The method of claim 6 wherein the mud acidizing solution contains from about 3 to about 25 weight percent HCl and from about 1 to about 10 weight percent HF, and wherein the concentration of the fluoboric acid is from about 2 to about 20 weight percent.
Claim 10
Dependent Claim
38 words
The method of claim 7 wherein the mud acid solution and the fluoboric acid solution are separated from one another during injection by a spacer comprising an aqueous solution of an ammonium halide or a weak organic acid.
Claim 11
Dependent Claim
21 words
The method of claim 8 wherein the spacer is an aqueous solution of an ammonium halide or a weak organic acid.
Claim 12
Dependent Claim
22 words
The method of claim 5 wherein the formation is also contacted with a preflush to dissolve carbonates prior to said mud acid.
Claim 13
Dependent Claim
12 words
The method of claim 10 wherein said preflush comprises aqueous fluoboric acid.
Claim 14
Dependent Claim
26 words
The method of claim 11 wherein the fluoboric acid preflush is shut in for a period of time prior to injection of the mud acidizing solution.
Claim 15
Dependent Claim
22 words
The method of claim 12 wherein the fluoboric acid solution injected in step (b) is shut in for a period of time.
Claim 16
Dependent Claim
21 words
The method of claim 5 wherein the fluoboric acid solution of step (b) is shut in for a period of time.
Claim 17
Dependent Claim
77 words
The method of claim 14 wherein the bottom hole static temperature of said well is from 100° F. to 300° F. and said shut in step is carried out for at least about as long as the following: ______________________________________
Minimum Shut-In Time
Bottom Hole Static Temperature ° F.
Hours
______________________________________
100 100
110 76
120 52
130 35
140 24
150 16
160 11
170 8
180 5
190 3
200-225 2
226-250 1
251-300 0.5
______________________________________
Claim 18
Dependent Claim
20 words
The method of claim 5 wherein said fluids are injected into said formation via a production well penetrating said formation.
Claim 19
Independent Claim
58 words
A method for increasing the permeability of a subterranean formation comprising injecting into said formation in sequence: (a) an aqueous solution of hydrochloric acid; (b) a spacer fluid selected from the group consisting of an aqueous solution of an ammonium halide or a weak organic acid, liquid hydrocarbons, and alcohols; and (c) an aqueous solution of fluoboric acid.
Claim 20
Independent Claim
58 words
A method for increasing the permeability of a subterranean formation comprising injecting into said formation in sequence: (a) an aqueous solution of hydrochloric acid; (b) a spacer fluid selected from the group consisting of an aqueous solution of an ammonium halide or a weak organic acid, liquid hydrocarbons, and alcohols; and (c) an aqueous solution of fluoboric acid.
Claim 21
Independent Claim
104 words
A method for increasing the permeability of a subterranean formation penetrated by a wellbore having a bottom hole static temperature of from 100° F. to 300° F., comprising (a) injecting into said formation, an aqueous solution of fluoboric acid; and (b) shutting in said well with said fluoboric acid in contact with said formation, for a period of time substantially according to the following schedule: ______________________________________
Minimum Shut-In Time
Bottom Hole Static Temperature ° F.
Hours
______________________________________
100 100
110 76
120 52
130 35
140 24
150 16
160 11
170 8
180 5
190 3
200-225 2
226-250 1
251-300 0.5
______________________________________
Claim 22
Independent Claim
104 words
A method for increasing the permeability of a subterranean formation penetrated by a wellbore having a bottom hole static temperature of from 100° F. to 300° F., comprising (a) injecting into said formation, an aqueous solution of fluoboric acid; and (b) shutting in said well with said fluoboric acid in contact with said formation, for a period of time substantially according to the following schedule: ______________________________________
Minimum Shut-In Time
Bottom Hole Static Temperature ° F.
Hours
______________________________________
100 100
110 76
120 52
130 35
140 24
150 16
160 11
170 8
180 5
190 3
200-225 2
226-250 1
251-300 0.5
______________________________________
Claim 23
Dependent Claim
23 words
The method of claim 18 including injecting an aqueous solution of hydrochloric acid in the formation ahead of said fluoboric acid injection step.
Claim 24
Dependent Claim
26 words
The method of claim 19 wherein the hydrochloric acid solution and the fluoboric acid solution are separated from one another during injection by a fluid spacer.
Claim 25
Dependent Claim
21 words
The method of claim 20 wherein the spacer is an aqueous solution of an ammonium halide or a weak organic acid.
Claim 26
Dependent Claim
22 words
The method of claim 18 including injecting an aqueous mud acidizing solution into the formation ahead of said fluoboric acid injection step.
Claim 27
Dependent Claim
47 words
The method of claim 22 wherein the mud acidizing solution contains from about 1 to about 37 weight percent HCl and from about 0.5 to about 25 weight percent HF, and wherein the concentration of the fluoboric acid is from about 1 to about 48 weight percent.
Claim 28
Dependent Claim
47 words
The method of claim 23 wherein the mud acidizing solution contains from about 3 to about 25 weight percent HCl and from about 1 to about 10 weight percent HF, and wherein the concentration of the fluoboric acid is from about 2 to about 20 weight percent.
Claim 29
Dependent Claim
26 words
The method of claim 22 wherein the mud acid solution and the fluoboric acid solution are separated from one another during injection by a fluid spacer.
Claim 30
Dependent Claim
21 words
The method of claim 25 wherein the spacer is an aqueous solution of an ammonium halide or a weak organic acid.
Claim 31
Independent Claim
40 words
A method for increasing the permeability of a subterranean formation penetrated by a production well, comprising injecting into said formation in sequence via said production well: (a) an aqueous mud acidizing solution; and (b) an aqueous solution of fluoboric acid.
Claim 32
Independent Claim
40 words
A method for increasing the permeability of a subterranean formation penetrated by a production well, comprising injecting into said formation in sequence via said production well: (a) an aqueous mud acidizing solution; and (b) an aqueous solution of fluoboric acid.
Claim 33
Dependent Claim
47 words
The method of claim 27 wherein the mud acidizing solution contains from about 1 to about 37 weight percent HCl and from about 0.5 to about 25 weight percent HF, and wherein the concentration of the fluoboric acid is from about 1 to about 48 weight percent.
Claim 34
Dependent Claim
47 words
The method of claim 28 wherein the mud acidizing solution contains from about 3 to about 25 weight percent HCl and from about 1 to about 10 weight percent HF, and wherein the concentration of the fluoboric acid is from about 2 to about 20 weight percent.
Claim 35
Dependent Claim
26 words
The method fo claim 27 wherein the mud acid solution and the fluoboric acid solution are separated from one another during injection by a fluid spacer.
Claim 36
Dependent Claim
21 words
The method of claim 30 wherein the spacer is an aqueous solution of an ammonium halide or a weak organic acid.
Claim 37
Dependent Claim
18 words
The method of claim 27 which includes a final step of producing formation fluids from said production well.
Claim 38
Dependent Claim
34 words
The method of claim 27 which includes shutting in said well for a period of time with said fluoboric acid in contact with said formation, and thereafter producing formation fluids from said production well.
Claim 39
Dependent Claim
80 words
The method of claim 33 wherein the bottom hole static temperature of said well is from 100° F. to 300° F. and said shut in step is carried out for a minimum time at least about as long as the following: ______________________________________
Minimum Shut-In Time
Bottom Hole Static Temperature ° F.
Hours
______________________________________
100 100
110 76
120 52
130 35
140 24
150 16
160 11
170 8
180 5
190 3
200-225 2
226-250 1
251-300 0.5
______________________________________
Claim 40
Independent Claim
89 words
A method for stimulating a siliceous clay containing formation to increase the production of fluids therefrom, wherein said formation is of the type which exhibits an initial production increase following a conventional mud acidizing treatment but which suffers a rapid production decline thereafter, which comprises injecting into said formation via a well penetrating said formation, an aqueous solution consisting substantially of fluoboric acid, so that the permeability of said formation is increased and so that fines are stabilized within said formation, thereby permitting a prolonged period of increased production.
Claim 41
Independent Claim
89 words
A method for stimulating a siliceous clay containing formation to increase the production of fluids therefrom, wherein said formation is of the type which exhibits an initial production increase following a conventional mud acidizing treatment but which suffers a rapid production decline thereafter, which comprises injecting into said formation via a well penetrating said formation, an aqueous solution consisting substantially of fluoboric acid, so that the permeability of said formation is increased and so that fines are stabilized within said formation, thereby permitting a prolonged period of increased production.
Claim 42
Dependent Claim
24 words
The method of claim 35 including shutting the well for a period of time while the fluoboric acid is in contact with said formation.
Claim 43
Dependent Claim
75 words
The method of claim 36 wherein the bottom hole static temperature of the well is from 100° F. to 300° F. and the well is shut in for at least about as long as the following: ______________________________________
Minimum Shut-In Time
Bottom Hole Static Temperature ° F.
Hours
______________________________________
100 100
110 76
120 52
130 35
140 24
150 16
160 11
170 8
180 5
190 3
200-225 2
226-250 1
251-300 0.5
______________________________________
Claim 44
Dependent Claim
12 words
The method of claim 35 wherein said well is a production well.
Claim 45
Dependent Claim
23 words
The method of claim 35 including injecting an aqueous solution of hydrochloric acid into the formation ahead of said fluoboric acid injection step.
Claim 46
Independent Claim
21 words
A method for stabilizing clays in a clay containing subterranean formation comprising contacting said clays with an aqueous fluoboric acid solution.
Claim 47
Independent Claim
21 words
A method for stabilizing clays in a clay containing subterranean formation comprising contacting said clays with an aqueous fluoboric acid solution.
Claim 48
Independent Claim
38 words
A method for increasing the permeability of a subterranean formation comprising injecting into said formation in sequence: (a) an aqueous solution of fluoboric acid; (b) an aqueous mud acidizing solution; and (c) an aqueous solution of fluoboric acid.
Claim 49
Independent Claim
38 words
A method for increasing the permeability of a subterranean formation comprising injecting into said formation in sequence: (a) an aqueous solution of fluoboric acid; (b) an aqueous mud acidizing solution; and (c) an aqueous solution of fluoboric acid.
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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) | 1982-04-30 | 1982-10-30 | 1983-05-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-04-30 | 1986-10-30 | 1987-05-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-04-30 | 1990-10-30 | 1991-05-01 | $7700.00 | Window Closed / Lapsed |