Patent US4309329A successfully refreshed from Google Patents.
US4309329A
Expired / Lapsed
US
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Aqueous drilling fluid additive
Assignee: Milchem Inc
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Filing: 1980-03-18
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Granted: 1982-01-05
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Expires: 2000-03-18
Abstract
Abstract The invention relates to an aqueous solution of a filtration control agent for utilization in said aqueous drilling fluid, useful in a method of forming a filter cake on the wall of a well for the reduction of filtrate from said drilling fluid, which is effective at high temperatures and pressures, the terpolymer consisting essentially of: (1) an alkali metal acrylate units; (2) hydroxyalkyl acrylate units; and (3) acrylamide.
Inventors
- 👤 James M. Lucas
- 👤 Alphonse C. Perricone
- 👤 Dorothy P. Enright
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 15:13
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/02; C09K8/04; C09K8/14; C09K8/18; C09K8/22; C09K8/24; C08; C08F; C08F220/00; C08F220/02; C08F220/04; C08F220/06; C08F220/52; C08F220/54; C08F220/56
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
108 words
An aqueous solution of a terpolymer filtration control agent for aqueous based drilling fluids having clayey material therein, said terpolymer consisting essentially of (1) from about 5 to about 62 mole percent of alkali metal acrylate units, (2) from about 2 to about 40 mole percent of hydroxyalkyl acrylate units selected from 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate and 2-hydroxybutyl acrylate units, and (3) from about 31 to about 91 mole percent of acrylamide units; a 0.2% by weight aqueous solution of said terpolymer having a viscosity at about 25° C. of from about 6 centipoises to about 85 centipoises, as determined at a shear rate of 511 reciprocal seconds.
Claim 2
Dependent Claim
108 words
An aqueous solution of a terpolymer filtration control agent for aqueous based drilling fluids having clayey material therein, said terpolymer consisting essentially of (1) from about 5 to about 62 mole percent of alkali metal acrylate units, (2) from about 2 to about 40 mole percent of hydroxyalkyl acrylate units selected from 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate and 2-hydroxybutyl acrylate units, and (3) from about 31 to about 91 mole percent of acrylamide units; a 0.2% by weight aqueous solution of said terpolymer having a viscosity at about 25° C. of from about 6 centipoises to about 85 centipoises, as determined at a shear rate of 511 reciprocal seconds.
Claim 3
Dependent Claim
29 words
The filtration control agent of claim 1 wherein the amount of said alkali metal acrylate units utilized in said terpolymer is from about 10 to about 30 mole percent.
Claim 4
Dependent Claim
20 words
The filtration control agent of claim 1 wherein the amount of said hydroxyalkyl acrylate units is about 4.0 mole percent.
Claim 5
Dependent Claim
23 words
The filtration control agent of claim 1 wherein the amount of said acrylamide units utilized in said terpolymer is about 70 mole percent.
Claim 6
Dependent Claim
44 words
The filtration control agent of claim 1 wherein the amount of said alkali metal acrylate units is about 23 mole percent; the amount of said hydroxyalkyl acrylate units is about 4.0 percent; and the amount of said acrylamide units is about 73 mole percent.
Claim 7
Dependent Claim
14 words
The filtration control agent of claim 1 wherein said hydroxyalkyl acrylate is 2-hydroxypropyl acrylate.
Claim 8
Dependent Claim
17 words
The filtration control agent of claim 1 wherein said alkali metal acrylate units are sodium acrylate units.
Claim 9
Dependent Claim
58 words
The filtration control agent of claim 1, wherein said alkali metal acrylate units are sodium acrylate units in an amount of about 23 mole percent; said hydroxyalkyl acrylate units are 2-hydroxypropyl acrylate units in an amount of about 4.0 mole percent; and said acrylamide units are present in said terpolymer in an amount of about 73 mole percent.
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) | 1985-01-04 | 1985-07-06 | 1986-01-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-01-04 | 1989-07-06 | 1990-01-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-01-04 | 1993-07-06 | 1994-01-05 | $7700.00 | Window Closed / Lapsed |