US4148360A
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US
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Method for acidizing high temperature subterranean formations
Assignee: Union Oil Company of California
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Filing: 1978-03-10
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Granted: 1979-04-10
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Expires: 1998-03-10
Abstract
Abstract Subterranean formations having temperatures between about 250° F. and about 700° F. are acidized by introducing a substantially anhydrous acid precursor through a well and into the formation, wherein the precursor hydrolyzes in situ to generate a hydrohalic acid. The acid precursor is a normally liquid, halogenated hydrocarbon having one or two carbon atoms per molecule which is thermally stable under the high temperature and pressure conditions encountered prior to hydrolysis.
Inventors
- 👤 David J. Watanabe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 08:05
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/60; C09K8/62; C09K8/72; Y; Y10; Y10S; Y10S507/00; Y10S507/933
Claims Analysis
Total Claims: 32
Claim 1
Independent Claim
120 words
A method for acidizing a subterranean formation having a temperature between about 250° F. and about 700° F., which comprises: introducing a substantially anhydrous treating fluid into a well communicating with said formation, said treating fluid consisting essentially of a normally liquid acid precursor having a generalized formula: C.sub.x H.sub.y X.sub.z wherein x= 1 or 2; y= 0, 1 or 2, but y≦ x; and z= 2x- y+ 2, and which is thermally stable under the temperature and pressure conditions in said well, or mixtures thereof; and displacing said treating fluid from said well and into said formation, wherein said acid precursor hydrolyzes in situ to generate a hydrohalic acid which reacts with said formation to increase the permeability thereof.
Claim 2
Independent Claim
120 words
A method for acidizing a subterranean formation having a temperature between about 250° F. and about 700° F., which comprises: introducing a substantially anhydrous treating fluid into a well communicating with said formation, said treating fluid consisting essentially of a normally liquid acid precursor having a generalized formula: C.sub.x H.sub.y X.sub.z wherein x= 1 or 2; y= 0, 1 or 2, but y≦ x; and z= 2x- y+ 2, and which is thermally stable under the temperature and pressure conditions in said well, or mixtures thereof; and displacing said treating fluid from said well and into said formation, wherein said acid precursor hydrolyzes in situ to generate a hydrohalic acid which reacts with said formation to increase the permeability thereof.
Claim 3
Dependent Claim
14 words
The method defined in claim 1 wherein said subterranean formation is a hydrocarbon-bearing formation.
Claim 4
Dependent Claim
58 words
The method defined in claim 2 wherein said treating fluid is introduced through an injection tubing disposed in said well and into a mixing zone at a point adjacent said formation, and further step the stop of introducing an aqueous fluid into said mixing zone to therein mix with said treating fluid prior to displacement into said formation.
Claim 5
Dependent Claim
35 words
The method defined in claim 1 wherein said subterranean formation contains an aqueous geothermal fluid, and wherein said acid precursor is introduced into said well through a substantially water-free injection tubing disposed in said well.
Claim 6
Dependent Claim
66 words
The method defined in claim 1 wherein said acid precursor is selected from the group consisting of tetrachloromethane, fluorotrichloromethane, bromotrichloromethane, dibromodichloromethane, trichloromethane, tribromomethane, chlorodibromomethane, bromodichloromethane, iododibromomethane, chlorodiiodomethane, iododichloromethane, fluorochlorobromomethane, 1,2-difluorotetrachloroethane, 1,1,2-trifluorotrichloroethane, 1,1,2-trifluorotribromoethane, pentachloroethane, fluorotetrachloroethane, fluorotetrabromoethane, difluorotribromoethane, 1,2-dichloro 1,1,2-tribromoethane, 1,2-dichloro 1,2,2-tribromoethane, dibromotrifluoroethane, dibromotrichloroethane, fluorodichlorodibromoethane, tetrachloroethane, tetrabromoethane, fluorotrichloroethane, 1-fluoro 1,1,2-tribromoethane, 1-fluoro 1,2,2-tribromoethane, difluorodichloroethane, 1,1,-difluoro, 1,2-dibromoethane, 1,1-difluoro 2,2-dibromoethane, chlorotribromoethane, 1,1,-dichloro 1,2-dibromoethane, 1,2-dichloro 1,2-dibromoethane, 1,1-dichloro 2,2-dibromoethane, bromotrichloroethane, and mixtures thereof.
Claim 7
Dependent Claim
28 words
The method defined in claim 1 wherein said acid precursor is selected from the group consisting of tetrachloromethane, bromotrichloromethane, trichloromethane, pentachloroethane, tetrachloroethane, 1,1,2-trichlorotrifluoroethane, fluorotetrachloroethane, fluorotrichloroethane and mixtures thereof.
Claim 8
Dependent Claim
11 words
The method of claim 1 wherein said acid precursor is tetrachloromethane.
Claim 9
Dependent Claim
16 words
The method of claim 1 wherein said acid precursor is a mixture of tetrachloromethane and 1,1,2-trichlorotrifluoroethane.
Claim 10
Dependent Claim
47 words
The method of claim 1 wherein said treating fluid is introduced into said well in a plurality of discrete slugs and including the step of introducing into said well a plurality of discrete slugs of an aqueous liquid interposed between said discrete slugs of said treating fluid.
Claim 11
Independent Claim
123 words
A method for acidizing a subterranean hydrocarbon-bearing formation having a temperature above about 250° F., comprising: introducing a substantially anhydrous treating fluid through a tubing disposed in a well and into a mixing zone of the well adjacent said formation, said treating fluid consisting essentially of an acid precursor selected from the group consisting of tetrachloromethane, bromotrichloromethane, trichloromethane, pentachloroethane, tetrachloroethane, 1,1,2-trichlorotrifluoroethane, fluorotetrachloroethane, fluorotrichloroethane and mixtures thereof; introducing an aqueous fluid into said mixing zone, wherein said acid precursor and said aqueous fluid mix to form a reaction mixture; and displacing said reaction mixture from said mixing zone and into said formation wherein said acid precursor hydrolyzes in situ to generate a hydrohalic acid which reacts with said formation to increase the permeability thereof.
Claim 12
Independent Claim
123 words
A method for acidizing a subterranean hydrocarbon-bearing formation having a temperature above about 250° F., comprising: introducing a substantially anhydrous treating fluid through a tubing disposed in a well and into a mixing zone of the well adjacent said formation, said treating fluid consisting essentially of an acid precursor selected from the group consisting of tetrachloromethane, bromotrichloromethane, trichloromethane, pentachloroethane, tetrachloroethane, 1,1,2-trichlorotrifluoroethane, fluorotetrachloroethane, fluorotrichloroethane and mixtures thereof; introducing an aqueous fluid into said mixing zone, wherein said acid precursor and said aqueous fluid mix to form a reaction mixture; and displacing said reaction mixture from said mixing zone and into said formation wherein said acid precursor hydrolyzes in situ to generate a hydrohalic acid which reacts with said formation to increase the permeability thereof.
Claim 13
Dependent Claim
31 words
The method defined in claim 10 wherein at least a part of the formation material to be acidized in said formation is calcium carbonate and wherein said acid precursor is tetrachloromethane.
Claim 14
Dependent Claim
40 words
The method of claim 10 wherein a plurality of discrete slugs of said treating fluid are introduced alternately with discrete slugs of said aqueous fluid through said tubing and into said mixing zone prior to displacement thereof into said formation.
Claim 15
Dependent Claim
27 words
The method of claim 10 wherein said aqueous fluid is introduced into said mixing zone through the annulus between said tubing and the walls of said well.
Claim 16
Dependent Claim
59 words
The method of claim 10 wherein at least a part of the formation material to be acidized in said formation is siliceous material, and wherein said treating fluid is introduced into said mixing zone as two discrete slugs, the first slug consisting essentially of tetrachloromethane and the second slug consisting essentially of a mixture of tetrachloromethane and 1,1,2-trichloro trifluoroethane.
Claim 17
Dependent Claim
42 words
The method of claim 14 wherein the ratio of said tetrachloromethane to said 1,1,2-trichlorotrifluoro ethane in said second slug is selected to produce, upon hydrolysis of said second slug, a hydrochloric acid to hydrofluoric acid ratio between about 2 and about 5.
Claim 18
Dependent Claim
45 words
The method defined in claim 10 wherein said aqueous fluid is an aqueous solution containing a water-soluble viscosity increasing agent, and including the step of simultaneously applying a high pressure to the injected fluids to thereby hydraulically fracture the formation as it is being acidized.
Claim 19
Dependent Claim
16 words
The method of claim 10 wherein said reaction mixture is displaced into said formation by nitrogen.
Claim 20
Dependent Claim
30 words
The method of claim 10 wherein said aqueous fluid is an aqueous liquid containing between about 50 and about 5000 standard cubic feet of nitrogen per barrel of aqueous liquid.
Claim 21
Independent Claim
106 words
A method for acidizing a subterranean formation having a temperature between about 400° F. and 700° F. and containing an aqueous geothermal fluid which comprises: introducing an anhydrous treating fluid through a tubing disposed in a well into a zone of the well adjacent said formation, said treating fluid consisting essentially of an acid precursor selected from the group consisting of tetrachloromethane, bromotrichloromethane, trichloromethane, pentachloroethane, tetrachloroethane, 1,1,2-trichlorotrifluoroethane, fluorotetrachloroethane, fluorotrichloroethane and mixtures thereof; and displacing said treating fluid from said zone and into said formation, wherein said acid precursor hydrolyzes in situ to generate a hydrohalic acid which reacts with the formation to increase the permeability thereof.
Claim 22
Independent Claim
106 words
A method for acidizing a subterranean formation having a temperature between about 400° F. and 700° F. and containing an aqueous geothermal fluid which comprises: introducing an anhydrous treating fluid through a tubing disposed in a well into a zone of the well adjacent said formation, said treating fluid consisting essentially of an acid precursor selected from the group consisting of tetrachloromethane, bromotrichloromethane, trichloromethane, pentachloroethane, tetrachloroethane, 1,1,2-trichlorotrifluoroethane, fluorotetrachloroethane, fluorotrichloroethane and mixtures thereof; and displacing said treating fluid from said zone and into said formation, wherein said acid precursor hydrolyzes in situ to generate a hydrohalic acid which reacts with the formation to increase the permeability thereof.
Claim 23
Dependent Claim
12 words
The method defined in claim 19 wherein said acid precursor is tetrachloromethane.
Claim 24
Dependent Claim
57 words
The method of claim 19 wherein at least a part of the formation material to be acidized in said formation is siliceous material, and wherein said treating fluid is introduced into said zone as two discrete slugs, the first slug consisting essentially of tetrachloromethane, and the second slug consisting essentially of a mixture of tetrachloromethane and 1,1,2-trichlorotrifluoroethane.
Claim 25
Dependent Claim
41 words
The method of claim 19 wherein the ratio of said tetrachloromethane to said 1,1,2-trichlorotrifluoroethane in said second slug is selected to produce, upon hydrolysis of said second slug, a hydrochloric acid to hydrofluoric acid ratio between about 2 and about 5.
Claim 26
Dependent Claim
30 words
The method defined in claim 19 including the step of simultaneously applying a high pressure to the injected fluid to thereby hydraulically fracture the formation as it is being acidized.
Claim 27
Independent Claim
144 words
A method for acidizing a subterranean formation having a temperature above about 400° F., which comprises: introducing a substantially anhydrous treating fluid into a well communicating with said formation, said treating fluid consisting essentially of a mixture of (1) a normally liquid acid precursor having a generalized formula: C.sub.x H.sub.y X.sub.z wherein x=1 or 2; y=0, 1 or 2, but y≦ x; and z=2x-y+2, and which is thermally stable under the temperature and pressure conditions in said well, and (2) a solvent refined, paraffinic lubricating oil base stock, or an acid-refined derivative thereof, composed of at least about 70 percent saturated hydrocarbons having normal boiling points above about 640° F.; and displacing said treating fluid from said well and into said formation, wherein said acid precursor hydrolyzes in situ to generate a hydrohalic acid which reacts with said formation to increase the permeability thereof.
Claim 28
Independent Claim
144 words
A method for acidizing a subterranean formation having a temperature above about 400° F., which comprises: introducing a substantially anhydrous treating fluid into a well communicating with said formation, said treating fluid consisting essentially of a mixture of (1) a normally liquid acid precursor having a generalized formula: C.sub.x H.sub.y X.sub.z wherein x=1 or 2; y=0, 1 or 2, but y≦ x; and z=2x-y+2, and which is thermally stable under the temperature and pressure conditions in said well, and (2) a solvent refined, paraffinic lubricating oil base stock, or an acid-refined derivative thereof, composed of at least about 70 percent saturated hydrocarbons having normal boiling points above about 640° F.; and displacing said treating fluid from said well and into said formation, wherein said acid precursor hydrolyzes in situ to generate a hydrohalic acid which reacts with said formation to increase the permeability thereof.
Claim 29
Dependent Claim
28 words
The method defined in claim 24 wherein said acid precursor is selected from the group consisting of tetrachloromethane, bromotrichloromethane, trichloromethane, pentachloroethane, tetrachloroethane, 1,1,2-trichlorotrifluoroethane, fluorotetrachloroethane, fluorotrichloroethane, and mixtures thereof.
Claim 30
Dependent Claim
27 words
The method defined in claim 25 wherein said subterranean formation has a temperature between about 500° F. and about 700° F. and contains an aqueous geothermal fluid.
Claim 31
Dependent Claim
41 words
The method defined in claim 24 wherein said treating fluid consists of from about 50 to about 95 weight percent of said acid precursor and the balance being said solvent refined, paraffinic lubricating oil base stock, or said acid-refined derivative thereof.
Claim 32
Dependent Claim
12 words
The method defined in claim 24 wherein said acid precursor is tetrachloromethane.
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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) | 1982-04-09 | 1982-10-09 | 1983-04-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-04-09 | 1986-10-09 | 1987-04-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-04-09 | 1990-10-09 | 1991-04-10 | $7700.00 | Window Closed / Lapsed |