Claims
- 1. 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.degree. C. of from about 6 centipoises to about 85 centipoises, as determined at a shear rate of 511 reciprocal seconds.
- 2. 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.
- 3. The filtration control agent of claim 1 wherein the amount of said hydroxyalkyl acrylate units is about 4.0 mole percent.
- 4. The filtration control agent of claim 1 wherein the amount of said acrylamide units utilized in said terpolymer is about 70 mole percent.
- 5. 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.
- 6. The filtration control agent of claim 1 wherein said hydroxyalkyl acrylate is 2-hydroxypropyl acrylate.
- 7. The filtration control agent of claim 1 wherein said alkali metal acrylate units are sodium acrylate units.
- 8. 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.
CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation-in-part application of co-pending application Ser. No. 946,227, filed Sept. 27, 1978, now abandoned, entitled "Aqueous Drilling Fluid Additive, Composition And Process", and assigned to the same assignee as this application.
US Referenced Citations (5)
Number |
Name |
Date |
Kind |
2552775 |
Fischer et al. |
May 1951 |
|
3726812 |
Higashimura et al. |
Apr 1973 |
|
3758449 |
Hoppe et al. |
Sep 1973 |
|
3764530 |
Burland et al. |
Oct 1973 |
|
3970633 |
Miller et al. |
Jul 1976 |
|
Continuation in Parts (1)
|
Number |
Date |
Country |
Parent |
946227 |
Sep 1978 |
|