US3884302A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Well cementing process
Assignee: Mobil Oil AS
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Filing: 1974-05-29
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Granted: 1975-05-20
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Expires: 1994-05-29
Abstract
Abstract This specification discloses a method of cementing casing in a well having a drilling mud therein. An alkaline flush having a pH of at least 10 is flowed through the annular space between the casing positioned in the well and the wall of the well. Thereafter, an aqueous base preflush having a characteristic of forming a viscous film at the interface between the preflush and an alkaline solution is flowed through the annular space to displace the alkaline flush and drilling mud therefrom. Thereafter a cement slurry, itself alkaline, is flowed into the annular space to displace the preflush and is allowed to set to bond the casing to the wall of the well.
Inventors
- 👤 Joseph U Messenger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 05:46
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/42
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
135 words
A method of cementing casing in a well having a drilling mud therein, comprising the steps of: a. flowing an aqueous alkaline wash having a pH of at least 10 into the annulus formed between said casing and the wall of the well; b. flowing an aqueous preflush into said annulus and in contact with said aqueous alkaline wash to displace said aqueous alkaline wash up said annulus, said aqueous preflush having a characteristic of forming a viscous film upon contact with a fluid having a pH of at least 10; c. flowing a cement slurry into said annulus and in contact with said aqueous preflush to displace said aqueous preflush up said annulus; and d. allowing said cement slurry to set in said annulus and bond said casing to said wall of the well.
Claim 2
Independent Claim
135 words
A method of cementing casing in a well having a drilling mud therein, comprising the steps of: a. flowing an aqueous alkaline wash having a pH of at least 10 into the annulus formed between said casing and the wall of the well; b. flowing an aqueous preflush into said annulus and in contact with said aqueous alkaline wash to displace said aqueous alkaline wash up said annulus, said aqueous preflush having a characteristic of forming a viscous film upon contact with a fluid having a pH of at least 10; c. flowing a cement slurry into said annulus and in contact with said aqueous preflush to displace said aqueous preflush up said annulus; and d. allowing said cement slurry to set in said annulus and bond said casing to said wall of the well.
Claim 3
Dependent Claim
30 words
The method of claim 1 wherein said aqueous alkaline wash is comprised of an aqueous solution of an alkali selected from the group consisting of sodium hydroxide or sodium carbonate.
Claim 4
Dependent Claim
23 words
The method of claim 2 wherein said aqueous alkaline wash is flowed into said well in an amount of at least 5 barrels.
Claim 5
Dependent Claim
22 words
The method of claim 2 wherein said aqueous preflush is comprised of water, a polysaccharide, and a cross-linking agent for the polysaccharide.
Claim 6
Dependent Claim
135 words
In a method of cementing casing in a well penetrating a subterranean formation wherein a cement slurry is flowed into the annulus formed intermediate the casing and the wall of the well and is allowed to set and bond the casing to the wall of the well, said well having a drilling mud therein, the improvement comprising: a. flowing in turbulent flow into said annulus an aqueous alkaline wash having a pH of at least 10; b. flowing in plug flow into said annulus and in contact with said aqueous alkaline wash an aqueous preflush that has a characteristic of forming a viscous film upon contact with a fluid having a pH of at least 10; and c. flowing in plug flow into said annulus and in contact with said aqueous preflush and cement slurry.
Claim 7
Dependent Claim
135 words
In a method of cementing casing in a well penetrating a subterranean formation wherein a cement slurry is flowed into the annulus formed intermediate the casing and the wall of the well and is allowed to set and bond the casing to the wall of the well, said well having a drilling mud therein, the improvement comprising: a. flowing in turbulent flow into said annulus an aqueous alkaline wash having a pH of at least 10; b. flowing in plug flow into said annulus and in contact with said aqueous alkaline wash an aqueous preflush that has a characteristic of forming a viscous film upon contact with a fluid having a pH of at least 10; and c. flowing in plug flow into said annulus and in contact with said aqueous preflush and cement slurry.
Claim 8
Independent Claim
145 words
A method of cementing casing in a well having an oil base drilling mud therein, comprising the steps of: a. flowing a light oil wash into the annulus formed between said casing and the wall of said well; b. flowing an aqueous alkaline wash having a pH of at least 10 into said annulus; c. flowing an aqueous prefLush into said annulus and in contact with said aqueous alkaline wash to displace said aqueous alkaline wash up said annulus, said aqueous preflush having a characteristic of forming a viscous film upon contact with a fluid having a pH of at least 10; d. flowing a cement slurry into said annulus in contact with said aqueous preflush to displace said aqueous preflush up said annulus; and e. allowing said cement slurry to set in said annulus and bond said casing to said wall of the well.
Claim 9
Independent Claim
145 words
A method of cementing casing in a well having an oil base drilling mud therein, comprising the steps of: a. flowing a light oil wash into the annulus formed between said casing and the wall of said well; b. flowing an aqueous alkaline wash having a pH of at least 10 into said annulus; c. flowing an aqueous prefLush into said annulus and in contact with said aqueous alkaline wash to displace said aqueous alkaline wash up said annulus, said aqueous preflush having a characteristic of forming a viscous film upon contact with a fluid having a pH of at least 10; d. flowing a cement slurry into said annulus in contact with said aqueous preflush to displace said aqueous preflush up said annulus; and e. allowing said cement slurry to set in said annulus and bond said casing to said wall of the well.
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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) | 1978-05-19 | 1978-11-18 | 1979-05-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-19 | 1982-11-18 | 1983-05-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-19 | 1986-11-18 | 1987-05-20 | $7700.00 | Window Closed / Lapsed |