US3581825A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Permafrost cementing process
Assignee: Mobil Oil AS
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Filing: 1969-12-09
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Granted: 1971-06-01
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Expires: 1989-12-09
Abstract
Abstract This specification discloses methods of treating wells drilled into the earth. These methods are particularly applicable for cementing behind casing located in wells drilled through permafrost zones. In carrying out these methods, slurries of calcium aluminate cement, clays selected from the group of bentonite, attapulgite and mixtures thereof, and water are formed and placed in the wells to be treated.
Inventors
- 👤 Joseph U Messenger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 23:28
CPC Classifications
C; C04; C04B; C04B14/00; C04B14/02; C04B14/04; C04B14/10; C09; C09K; C09K8/00; C09K8/42
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
39 words
The process of claim 1 wherein water is present in an amount of about 2.8 gallons per each 1 percent of clay in excess of the amount of water required to form a pumpable slurry of calcium aluminate cement.
Claim 2
Dependent Claim
23 words
The process of claim 1 wherein said clay is present in an amount no greater than 3 percent by weight based on cement.
Claim 3
Dependent Claim
23 words
The process of claim 1 wherein said clay is bentonite in an amount no greater than 6 percent by weight based on cement.
Claim 4
Dependent Claim
23 words
The process of claim 4 wherein said bentonite is present in an amount no greater than 3 percent by weight based on cement.
Claim 5
Dependent Claim
23 words
The process of claim 1 wherein said clay is attapulgite in an amount no greater than 6 percent be weight based on cement.
Claim 6
Dependent Claim
23 words
The process of claim 6 wherein said attapulgite is present in an amount no greater than 3 percent by weight based on cement.
Claim 7
Dependent Claim
109 words
In a process of treating a well penetrating a permafrost zone of the earth, the steps comprising: a. forming a cement slurry comprising a mixture of calcium aluminate cement, clay selected from the group consisting of bentonite and attapulgite and mixtures thereof wherein said clay is present in an amount of no greater than 6 percent by weight based on cement, and water in an amount of at least 2.0 gallons per each 1 percent of clay in excess of the amount of water required to form a pumpable slurry of calcium aluminate cement; b. positioning said slurry adjacent said permafrost zone; and c. allowing said slurry to set.
Claim 8
Dependent Claim
39 words
The process of claim 8 wherein said clay is a mixture of bentonite present in an amount of 1.125 percent by weight based on cement and attapulgite present in an amount of 0.375 percent by weight based on cement.
Claim 9
Dependent Claim
23 words
The process of claim 8 wherein the amounts of bentonite and attapulgite vary between the ratios of 2:1 and 5:1 bentonite to attapulgite.
Claim 10
Dependent Claim
69 words
In a well equipped with casing and penetrating a permafrost zone of the earth, a body of set cement surrounding said casing within said permafrost zone, said set cement being comprised of calcium aluminate cement and clay selected from the group consisting of attapulgite and mixtures of attapulgite and bentonite, wherein said clay is present in an amount of no greater than 6 percent by weight based on cement.
Claim 11
Dependent Claim
151 words
In a process of treating a well equipped with casing penetrating a permafrost zone of the earth, the steps comprising: a. forming a cement slurry comprising calcium aluminate cement, clay selected from the group comprising bentonite and attapulgite and mixtures thereof, wherein said clay is present in an amount of no greater than 6 percent by weight based on cement, and water of a temperature of about 40* F. to 45* F. in an amount of at least 2.0 gallons per each 1 percent of clay in excess of the amount of water required to form a pumpable slurry of calcium aluminate cement; b. pumping said slurry down said well; c. displacing said slurry from said well with a displacing liquid at a temperature of about 40* F. to 45* F. wherein said slurry is positioned intermediate said casinG and said permafrost zone; and d. allowing said slurry to set therein.
Claim 12
Dependent Claim
31 words
The process of claim 12 further comprising prior to step (d) circulating fluid at a temperature greater than 32* F. through said well in indirect heat exchange with said cement slurry.
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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) | 1974-05-31 | 1974-11-30 | 1975-06-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-31 | 1978-11-30 | 1979-06-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-31 | 1982-11-30 | 1983-06-01 | $7700.00 | Window Closed / Lapsed |