US3760876A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Well completion systems
Assignee: Mobil Oil AS
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Filing: 1972-05-11
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Granted: 1973-09-25
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Expires: 1992-05-11
Abstract
Abstract Well completion system for wells penetrating a permafrost zone in the earth. The system comprises a protective casing and a production casing extending to a subterranean formation. The production casing is suspended from the protective casing at a downhole location in order to reduce loading at the wellhead. Also disclosed are means for supporting other tubular goods within the well rather than at the wellhead.
Inventors
- 👤 E Blount
- 👤 N Prueger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 10:24
CPC Classifications
E; E21; E21B; E21B36/00; E21B36/02; E21B43/00; E21B43/02; E21B43/10; Y; Y10; Y10S; Y10S166/00; Y10S166/901
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
160 words
In a well extending from a wellhead through a permafrost zone of the earth to an underlying subterranean formation, the combination comprising: an outer conductor casing within said well extending downwardly from the wellhead, a protective casing within said conductor casing extending downwardly from the wellhead into said permafrost zone, a production casing within said protective casing extending from the wellhead through said permafrost zone to the subterranean formation, support means at a downhole location within said protective casing and below the top of said permafrost zone for suspending a lower section of said production casing from said protective casing, and selectively releasable connecting means in said production casing at a downhole location below said conductor casing and above said support means for allowing an upper section of said production casing to be selectively disconnected from a lower section of said production casing whereby said upper section may be withdrawn from said well while leaving said lower section in place.
Claim 2
Dependent Claim
160 words
In a well extending from a wellhead through a permafrost zone of the earth to an underlying subterranean formation, the combination comprising: an outer conductor casing within said well extending downwardly from the wellhead, a protective casing within said conductor casing extending downwardly from the wellhead into said permafrost zone, a production casing within said protective casing extending from the wellhead through said permafrost zone to the subterranean formation, support means at a downhole location within said protective casing and below the top of said permafrost zone for suspending a lower section of said production casing from said protective casing, and selectively releasable connecting means in said production casing at a downhole location below said conductor casing and above said support means for allowing an upper section of said production casing to be selectively disconnected from a lower section of said production casing whereby said upper section may be withdrawn from said well while leaving said lower section in place.
Claim 3
Dependent Claim
26 words
The system of claim 1 wherein said support means for said lower section of production casing is located at a depth of at least 500 feet.
Claim 4
Dependent Claim
20 words
The system of claim 1 wherein said support means is located below the free ice section of said permafrost zone.
Claim 5
Dependent Claim
162 words
In a well extending from a wellhead through a permafrost zone of the earth to an underlying subterranean formation, the combination comprising: an outer conductor casing within said well extending downwardly from the wellhead, a protective casing within said conductor casing extending downwardly from the wellhead through said permafrost zone to a location below said permafrost zone, a production casing within said protective casing extending from the wellhead through said permafrost zone to the subterranean formation, support means within said protective casing for suspending a lower section of said production casing from said protective casing at a location below said permafrost zone, and selectively releasable connecting means in said prodUction casing at a downhole location below said conductor casing and above said support means for allowing an upper section of said production casing to be selectively disconnected from a lower section of said production casing whereby said upper section may be withdrawn from said well while leaving said lower section in place.
Claim 6
Dependent Claim
162 words
In a well extending from a wellhead through a permafrost zone of the earth to an underlying subterranean formation, the combination comprising: an outer conductor casing within said well extending downwardly from the wellhead, a protective casing within said conductor casing extending downwardly from the wellhead through said permafrost zone to a location below said permafrost zone, a production casing within said protective casing extending from the wellhead through said permafrost zone to the subterranean formation, support means within said protective casing for suspending a lower section of said production casing from said protective casing at a location below said permafrost zone, and selectively releasable connecting means in said prodUction casing at a downhole location below said conductor casing and above said support means for allowing an upper section of said production casing to be selectively disconnected from a lower section of said production casing whereby said upper section may be withdrawn from said well while leaving said lower section in place.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-09-24 | 1977-03-26 | 1977-09-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-24 | 1981-03-26 | 1981-09-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-24 | 1985-03-26 | 1985-09-25 | $7700.00 | Window Closed / Lapsed |