US3763935A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Well insulation method
Assignee: Atlantic Richfield Co
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Filing: 1972-05-15
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Granted: 1973-10-09
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Expires: 1992-05-15
Abstract
Abstract A method for terminally insulating one or more casing strings from the walls of a wellbore which includes employing annular zones in which at least part of the air has been displaced and replaced by a gas which remains gaseous under the temperature and pressure conditions obtaining in the annular zone when placed in the wellbore and which has a thermal conductivity substantially less than that of air.
Inventors
- 👤 T Perkins
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 19:53
CPC Classifications
E; E21; E21B; E21B36/00; E21B36/003; E21B17/00; E21B17/02; E21B17/04
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
173 words
In a method for thermally insulating from the permafrosT walls of a wellbore the interior of a casing string formed from a plurality of casing sections, the improvement comprising providing at least one closed air containing annular zone around and along at least part of the interior to be insulated, displacing a substantial portion of said air from said annular zone, replacing at least part of said displaced air with a gas which is substantially inert to the materials forming said annular zone, said gas in said annular zone being at a temperature no greater than about 32*F., said gas having a thermal conductivity at 32*F. of substantially less than 5.572 X 10 5 gram-calories/(second)(square centimeter)(*C./centimeter), the pressure in said annular zone being below the vapor pressure of the gas components present in said annular zone, said pressure being from about 10 5 to about 1,500 millimeters of mercury, and disposing said annular zone in said wellbore between the interior portion of said casing to be insulated and the walls of said wellbore.
Claim 2
Dependent Claim
173 words
In a method for thermally insulating from the permafrosT walls of a wellbore the interior of a casing string formed from a plurality of casing sections, the improvement comprising providing at least one closed air containing annular zone around and along at least part of the interior to be insulated, displacing a substantial portion of said air from said annular zone, replacing at least part of said displaced air with a gas which is substantially inert to the materials forming said annular zone, said gas in said annular zone being at a temperature no greater than about 32*F., said gas having a thermal conductivity at 32*F. of substantially less than 5.572 X 10 5 gram-calories/(second)(square centimeter)(*C./centimeter), the pressure in said annular zone being below the vapor pressure of the gas components present in said annular zone, said pressure being from about 10 5 to about 1,500 millimeters of mercury, and disposing said annular zone in said wellbore between the interior portion of said casing to be insulated and the walls of said wellbore.
Claim 3
Dependent Claim
22 words
A method according to claim 1 wherein said thermal conductivity of said gas is less than 5.300 X 10 5 gram-calories/(second)(square centimeter)(*C./centimeter).
Claim 4
Dependent Claim
36 words
A method according to claim 1 wherein a plurality of concentric casing strings are placed in said wellbore and at least one of said casing strings is provided with at least one of said annular zones.
Claim 5
Dependent Claim
39 words
A method according to claim 3 wherein a plurality of said casing strings is provided with a plurality of said annular zones along at least part of the length of at least one of said plurality of casing strings.
Claim 6
Dependent Claim
54 words
A method according to claim 1 wherein said gas is at least one of acetone, ammonia, argon, benzene, carbon dioxide, carbon disulfide, chlorine, chloroform, methane, ethane, propane, ethyl alcohol, ethyl ether, methyl alcohol, methyl ether, methylethylether, ethylene, hydrogen sulfide, methyl halide, ethyl halide, ethylene halide, nitrous oxide, n-butane, isobutane, n-pentane, isopentane, and sulfur dioxide.
Claim 7
Dependent Claim
34 words
A method according to claim 5 wherein said gas is at a temperature of from about 14* to about 32*F. and a pressure of from about 10 5 to about 760 millimeters of mercury.
Claim 8
Dependent Claim
23 words
A method according to claim 4 wherein solid thermal insulation is provided between adjacent zones of adjacent casing sections in a casing string.
Claim 9
Dependent Claim
15 words
A method according to claim 1 wherein said at least one annular zone contains insulation.
Claim 10
Dependent Claim
22 words
A method according to claim 5 wherein said methyl halide, ethyl halide, and ethylene halide contain from one to six halogen atoms.
Claim 11
Dependent Claim
25 words
A method according to claim 9 wherein when at least two halogen atoms are present in the halide, the atoms are different types of halogens.
References Cited (Backward Citations)
US3380530A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-10-08 | 1977-04-09 | 1977-10-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-08 | 1981-04-09 | 1981-10-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-08 | 1985-04-09 | 1985-10-09 | $7700.00 | Window Closed / Lapsed |