US3677340A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Permafrost completion
Assignee: Mobil Oil AS
•
Filing: 1970-07-23
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Granted: 1972-07-18
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Expires: 1990-07-23
Abstract
Abstract This specification discloses completion methods for wells drilled through permafrost zones of the earth. Two concentric strings of casing are set in a well and liquid is withdrawn from the annulus intermediate these casing strings adjacent the permafrost zones, leaving the annulus dry. Thereafter, insulation is installed in the dry annulus adjacent the permafrost zones.
Inventors
- 👤 Elmo M Blount
- 👤 Earl S Snavely Jr
- 👤 Joseph U Messenger
- 👤 Nicolas J Prueger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 23:58
CPC Classifications
E; E21; E21B; E21B33/00; E21B33/10; Y; Y10; Y10S; Y10S166/00; Y10S166/901
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
137 words
In a process of completing a well penetrating a permafrost zone of the earth, the steps comprising: a. lowering a surface string of casing into said well, said surface string extending from the earth''s surface and penetrating said permafrost zone; b. lowering a production string of casing through said surface string into said well, said production string extending from said earth surface through said permafrost and terminating below said surface string and forming an annulus intermediate said surface string and said production string; c. opening a passage located in said production string thereby providing fluid communication between said production string and said annulus and swabbing said production string and lowering the liquid level in said production string and said annulus thereby withdrawing accumulative liquid from said annulus; and d. installing insulation in said annulus adJacent said permafrost.
Claim 2
Dependent Claim
137 words
In a process of completing a well penetrating a permafrost zone of the earth, the steps comprising: a. lowering a surface string of casing into said well, said surface string extending from the earth''s surface and penetrating said permafrost zone; b. lowering a production string of casing through said surface string into said well, said production string extending from said earth surface through said permafrost and terminating below said surface string and forming an annulus intermediate said surface string and said production string; c. opening a passage located in said production string thereby providing fluid communication between said production string and said annulus and swabbing said production string and lowering the liquid level in said production string and said annulus thereby withdrawing accumulative liquid from said annulus; and d. installing insulation in said annulus adJacent said permafrost.
Claim 3
Dependent Claim
11 words
The process of claim 1 wherein said insulation is polyurethane foam.
Claim 4
Dependent Claim
12 words
The process of claim 2 wherein said insulation is molded polyurethane foam.
Claim 5
Dependent Claim
30 words
The method of claim 1 wherein said insulation is installed by removing a portion of said production string from said well and installing an insulated production string in said well.
Claim 6
Dependent Claim
90 words
A well penetrating a permafrost zone of the earth comprising: a first string of casing extending at least 750 feet from the earth''s surface; a second concentric string of casing within said first string and extending below the bottom of said permafrost zone; a circulating valve in said second concentric string of casing located at least 750 feet below said earth''s surface; means sealing said annulus to provide at least 750 feet of dry annulus below said earth''s surface; and insulation located in said dry annulus adjacent said permafrost zone.
Claim 7
Dependent Claim
90 words
A well penetrating a permafrost zone of the earth comprising: a first string of casing extending at least 750 feet from the earth''s surface; a second concentric string of casing within said first string and extending below the bottom of said permafrost zone; a circulating valve in said second concentric string of casing located at least 750 feet below said earth''s surface; means sealing said annulus to provide at least 750 feet of dry annulus below said earth''s surface; and insulation located in said dry annulus adjacent said permafrost zone.
Claim 8
Dependent Claim
10 words
The apparatus of claim 5 wherein said insulation is polyurethane.
Claim 9
Dependent Claim
12 words
The apparatus of claim 6 wherein said insulation is molded polyurethane foam.
Claim 10
Dependent Claim
31 words
The apparatus of claim 5 further comprising a backoff joint in said second concentric string of casing located above said circulating valve and at least 700 feet below said earth''s surface.
References Cited (Backward Citations)
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Cited
US3280909A
Cited
US3511282A
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US3511282B1
Cited
US3397745A
Cited
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Cited
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Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-07-18 | 1976-01-17 | 1976-07-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-18 | 1980-01-17 | 1980-07-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-18 | 1984-01-17 | 1984-07-18 | $7700.00 | Window Closed / Lapsed |