US4699225A
Expired / Lapsed
US
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Drilling fluids containing AMPS, acrylic acid, itaconic acid polymer
Assignee: Diamond Shamrock Chemicals Co
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Filing: 1985-11-07
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Granted: 1987-10-13
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Expires: 2005-11-07
Abstract
Abstract Polymers of (1) from about 5% to about 50% by weight of 2-acrylamido-2-methylpropane sulfonic acid and (2) from about 95% to about 50% by weight of a second component, there being from 100% to about 80% by weight acrylic acid and from 0% to about 20% by weight of itaconic acid in the second component and having a weight average molecular weight of between about 50,000 to about 1,000,000 and which are at least water dispersible are used as fluid loss control additives for aqueous drilling fluids and are particularly advantageous when used with muds containing soluble calcium ions and muds containing chloride ions such as seawater muds. An example is a copolymer of 10% by weight 2-acrylamido-2-methylpropane sulfonic acid and 90% by weight acrylic acid in its sodium salt form.
Inventors
- 👤 Dinshaw F. Bardoliwalla
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 16:34
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; C09K8/06; C09K8/12
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
111 words
An aqueous drilling fluid having present in an amount sufficient to reduce fluid loss of said drilling fluid, at least one polymer of (1) from about 5% to about 50% by weight of 2-acrylamido-2-methylpropane sulfonic acid and (2) from about 95% to about 50% by weight of a second component, there being from 100% to about 80% by weight of acrylic acid and from 0% by weight to about 20% by weight of itaconic acid in the second component, said polymer having a weight average molecular weight of between about 50,000 to about 1,000,000 being in its free acid or partially or completely neutralized form and being at least water dispersible.
Claim 2
Dependent Claim
111 words
An aqueous drilling fluid having present in an amount sufficient to reduce fluid loss of said drilling fluid, at least one polymer of (1) from about 5% to about 50% by weight of 2-acrylamido-2-methylpropane sulfonic acid and (2) from about 95% to about 50% by weight of a second component, there being from 100% to about 80% by weight of acrylic acid and from 0% by weight to about 20% by weight of itaconic acid in the second component, said polymer having a weight average molecular weight of between about 50,000 to about 1,000,000 being in its free acid or partially or completely neutralized form and being at least water dispersible.
Claim 3
Dependent Claim
22 words
The drilling fluid of claim 1 wherein the weight average molecular weight of said polymer is between about 100,000 to about 500,000.
Claim 4
Dependent Claim
19 words
The drilling fluid of claim 2 wherein said drilling fluid is a mud containing soluble calcium or chloride ions.
Claim 5
Dependent Claim
30 words
The drilling fluid composition of claim 3 wherein said polymer is present in an amount of from about 0.5 to about 10 pounds per 42 gallon barrel of drilling fluid.
Claim 6
Dependent Claim
49 words
The drilling fluid composition of claim 4 wherein said polymer is in the form of at least one free acid or partial or complete sodium, potassium, ammonium, organic amine or quaternary ammonium salt, said salt containing one or more of sodium, potassium, ammonium, organic amine or quaternary ammonium cations.
Claim 7
Dependent Claim
49 words
The drilling fluid composition of claim 5 wherein said polymer is a copolymer of about 10% by weight 2-acrylamido-2-methylpropane sulfonic acid and about 90% by weight acrylic acid in the form of its free acid or partially or completely neutralized sodium, potassium, ammonium, organic amine or quaternary ammonium salt.
Claim 8
Dependent Claim
49 words
The drilling fluid composition of claim 5 wherein said polymer is a copolymer of about 30% by weight 2-acrylamido-2-methylpropane sulfonic acid and about 70% by weight acrylic acid in the form of its free acid or partially or completely neutralized sodium, potassium, ammonium, organic amine or quaternary ammonium salt.
Claim 9
Dependent Claim
49 words
The drilling fluid composition of claim 5 wherein said polymer is a copolymer of about 40% by weight 2-acrylamido-2-methylpropane sulfonic acid and about 60% by weight acrylic acid in the form of its free acid or partially or completely neutralized sodium, potassium, ammonium, organic amine or quaternary ammonium salt.
Claim 10
Dependent Claim
48 words
The drilling fluid composition of claim 5 wherein said polymer is a copolymer of about 20% by weight 2-acrylamido-2-methylpropane sulfonic acid and about 80% by weight acrylic acid in the form of its free acid or partially or completely neutralized sodium, potassium, ammonium, organic amine or quaternary salt.
Claim 11
Dependent Claim
55 words
The drilling fluid composition of claim 5 wherein said polymer is a terpolymer of about 19% by weight 2-acrylamido-2-methylpropane sulfonic acid, about 76% by weight acrylic acid and about 5% by weight itaconic acid in the form of its free acid or partially or completely neutralized sodium, potassium, ammonium, organic amine or quaternary ammonium salt.
Claim 12
Dependent Claim
55 words
The drilling fluid composition of claim 5 wherein said polymer is a terpolymer of about 38% by weight 2-acrylamido-2-methylpropane sulfonic acid, about 57% by weight acrylic acid and about 5% by weight itaconic acid in the form of its free acid or partially or completely neutralized sodium, potassium, ammonium, organic amine or quaternary ammonium salt.
Claim 13
Dependent Claim
55 words
The drilling fluid composition of claim 5 wherein said polymer is a terpolymer of about 18% by weight 2-acrylamido-2-methylpropane sulfonic acid, about 72% by weight acrylic acid and about 10% by weight itaconic acid in the form of its free acid or partially or completely neutralized sodium, potassium, ammonium, organic amine or quaternary ammonium salt.
Claim 14
Dependent Claim
55 words
The drilling fluid composition of claim 5 wherein said polymer is a terpolymer of about 36% by weight 2-acrylamido-2-methylpropane sulfonic acid, about 54% by weight acrylic acid and about 10% by weight itaconic acid in the form of its free acid or partially or completely neutralized sodium, potassium, ammonium, organic amine or quaternary ammonium salt.
Claim 15
Dependent Claim
135 words
In a method of drilling a well into a subterranean formation in which an aqueous drilling fluid is circulated into the well, the step of circulating said drilling fluid, containing in an amount sufficient to reduce fluid loss of said drilling fluid, at least one polymer of (1) from about 5% to about 50% by weight of 2-acrylamido-2-methylpropane sulfonic acid and (2) from about 95% to about 50% by weight of a second component, there being from 100% to about 80% by weight of acrylic acid and from 0% by weight to about 20% by weight of itaconic acid in the second component, said polymer having a weight average molecular weight of between about 50,000 to about 1,000,000, being in its free acid or partially or completely neutralized form and being at least water dispersible.
Claim 16
Dependent Claim
135 words
In a method of drilling a well into a subterranean formation in which an aqueous drilling fluid is circulated into the well, the step of circulating said drilling fluid, containing in an amount sufficient to reduce fluid loss of said drilling fluid, at least one polymer of (1) from about 5% to about 50% by weight of 2-acrylamido-2-methylpropane sulfonic acid and (2) from about 95% to about 50% by weight of a second component, there being from 100% to about 80% by weight of acrylic acid and from 0% by weight to about 20% by weight of itaconic acid in the second component, said polymer having a weight average molecular weight of between about 50,000 to about 1,000,000, being in its free acid or partially or completely neutralized form and being at least water dispersible.
Claim 17
Dependent Claim
21 words
The method of claim 14 wherein the weight average molecular weight of said copolymer is between about 100,000 to about 500,000.
Claim 18
Dependent Claim
18 words
The method of claim 15 wherein said drilling fluid is a mud containing soluble calcium or chloride ions.
Claim 19
Dependent Claim
32 words
The method of claim 16 wherein said polymer is present in said drilling fluid in an amount of from about 0.5 to about 10 pounds per 42 gallon barrel of drilling fluid.
Claim 20
Dependent Claim
47 words
The method of claim 17 wherein said polymer is in the form of at least one free acid or partial or complete sodium, potassium, ammonium, organic amine or quaternary ammonium salt, said salt containing one or more of sodium, potassium, ammonium, organic amine or quaternary ammonium cations.
Claim 21
Dependent Claim
48 words
The method of claim 18 wherein said polymer is a copolymer of from about 10% by weight 2-acrylamido-2-methylpropane sulfonic acid and about 90% by weight acrylic acid in the form of its free acid or partially or completely neutralized sodium, potassium, ammonium, organic amine or quaternary ammonium salt.
Claim 22
Dependent Claim
48 words
The method of claim 18 wherein said polymer is a copolymer of from about 30% by weight 2-acrylamido-2-methylpropane sulfonic acid and about 70% by weight acrylic acid in the form of its free acid or partially or completely neutralized sodium, potassium, ammonium, organic amine or quaternary ammonium salt.
Claim 23
Dependent Claim
48 words
The method of claim 18 wherein said polymer is a copolymer of from about 40% by weight 2-acrylamido-2-methylpropane sulfonic acid and about 60% by weight acrylic acid in the form of its free acid or partially or completely neutralized sodium, potassium, ammonium, organic amine or quaternary ammonium salt.
Claim 24
Dependent Claim
48 words
The method of claim 18 wherein said polymer is a copolymer of from about 20% by weight 2-acrylamido-2-methylpropane sulfonic acid and about 80% by weight acrylic acid in the form of its free acid or partially or completely neutralized sodium, potassium, ammonium, organic amine or quaternary ammonium salt.
Claim 25
Dependent Claim
53 words
The method of claim 18 wherein said polymer is a terpolymer of about 19% by weight 2-acrylamido-2-methylpropane sulfonic acid, about 76% by weight acrylic acid and about 5% by weight itaconic acid in the form of its free acid or partially or completely neutralized sodium, potassium, ammonium, organic amine or quaternary ammonium salt.
Claim 26
Dependent Claim
53 words
The method of claim 18 wherein said polymer is a terpolymer of about 38% by weight 2-acrylamido-2-methylpropane sulfonic acid, about 57% by weight acrylic acid and about 5% by weight itaconic acid in the form of its free acid or partially or completely neutralized sodium, potassium, ammonium, organic amine or quaternary ammonium salt.
Claim 27
Dependent Claim
53 words
The method of claim 18 wherein said polymer is a terpolymer of about 18% by weight 2-acrylamido-2-methylpropane sulfonic acid, about 72% by weight acrylic acid and about 10% by weight itaconic acid in the form of its free acid or partially or completely neutralized sodium, potassium, ammonium, organic amine or quaternary ammonium salt.
Claim 28
Dependent Claim
53 words
The method of claim 18 wherein said polymer is a terpolymer of about 36% by weight 2-acrylamido-2-methylpropane sulfonic acid, about 54% by weight acrylic acid and about 10% by weight itaconic acid in the form of its free acid or partially or completely neutralized sodium, potassium, ammonium, organic amine or quaternary ammonium salt.
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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) | 1990-10-12 | 1991-04-13 | 1991-10-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-10-12 | 1995-04-13 | 1995-10-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-10-12 | 1999-04-13 | 1999-10-13 | $7700.00 | Window Closed / Lapsed |