US4540496A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Intramolecular polymer complexes - viscosifiers for high ionic strength drilling fluids
Assignee: ExxonMobil Technology and Engineering Co
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Filing: 1983-03-25
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Granted: 1985-09-10
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Expires: 2003-03-25
Abstract
Abstract A new family of terpolymers based on acrylamide/sodium styrene sulfonate/methacrylamidopropyltrimethylammonium chloride has been found to be an improved viscosity control additive for water-based drilling muds. The resultant muds display good viscosity characteristics, thermal stability and gel strength when formulated from the terpolymer intramolecular complex having the appropriate polymer concentration and salt level.
Inventors
- 👤 Dennis G. Peiffer
- 👤 Robert D. Lundberg
- 👤 Thad O. Walker
- 👤 S. Richard Turner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 14:24
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/02; C09K8/04; C09K8/06; C09K8/12; C08; C08F; C08F220/00; C08F220/02; C08F220/52; C08F220/54; C08F220/56; C09K8/14; C09K8/18; C09K8/22; C09K8/24
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
180 words
A drilling mud which comprises: (a) salt water having about 0.1 to about 50 grams of salt per 100 ml. of water; (b) about 4 to about 30 lbs/bbl of clay; (c) about 1 to about 30 lbs/bbl of a lignosulfonate; (d) weighting material of sufficient quantity necessary to achieve the desired density; (e) about 0.25 to about 5 lbs/bbl of a terpolymer having the formula: ##STR2## wherein x is about 40 to about 98 mole %, y is about 1 to about 50 mole %, z is about 1 to about 50 mole percent, wherein y and z are less than 60 mole %, and M is selected from the group consisting of amines and a metallic cation being selected from the group consisting of lead, iron, aluminum, Groups IA, IIA, IB and II of the Periodic Table of Elements, the molecular weight of said terpolymer as measured by intrinsic viscosity being 1×10 3 to 5×10 6 ; and (f) base of sufficient quantity to adjust the pH of the water-based drilling mud to about 10 to about 10.5.
Claim 2
Dependent Claim
180 words
A drilling mud which comprises: (a) salt water having about 0.1 to about 50 grams of salt per 100 ml. of water; (b) about 4 to about 30 lbs/bbl of clay; (c) about 1 to about 30 lbs/bbl of a lignosulfonate; (d) weighting material of sufficient quantity necessary to achieve the desired density; (e) about 0.25 to about 5 lbs/bbl of a terpolymer having the formula: ##STR2## wherein x is about 40 to about 98 mole %, y is about 1 to about 50 mole %, z is about 1 to about 50 mole percent, wherein y and z are less than 60 mole %, and M is selected from the group consisting of amines and a metallic cation being selected from the group consisting of lead, iron, aluminum, Groups IA, IIA, IB and II of the Periodic Table of Elements, the molecular weight of said terpolymer as measured by intrinsic viscosity being 1×10 3 to 5×10 6 ; and (f) base of sufficient quantity to adjust the pH of the water-based drilling mud to about 10 to about 10.5.
Claim 3
Dependent Claim
13 words
A water-based drilling mud according to claim 1 wherein said clay is Bentonite.
Claim 4
Dependent Claim
14 words
A water-based drilling mud according to claim 1 wherein said base is sodium hydroxide.
Claim 5
Dependent Claim
12 words
A water-based drilling mud according to claim 1 wherein M is sodium.
Claim 6
Dependent Claim
116 words
A drilling mud which comprises: (a) salt water having about 0.1 to about 50 grams of salt per 100 grams of water; and (b) about 0.25 to about 15 lbs/bbl of the acrylamide-based polyampholyte containing low to moderate levels of anionic and cationic groups to increase the viscosity of said drilling mud, said terpolymer containing acrylamide monomer units and having about 1 to about 50 mole % of the charged monomer units, said terpolymer possessing unequal molar ratio of anionic and cationic monomers, said anionic monomer being sodium styrene sulfonate, and said cationic monomer being selected from the group consisting of methacrylamidopropyltrimethylammonium chloride, dimethyldiallylammonium chloride, diethyldiallylammonium chloride, 2-methacryloxy-2-ethyltrimethylammonium chloride, trimethylmethacryloxethylammonium methosulfate, 2-acrylamido-2-methylpropyltrimethylammonium chloride, and vinylbenzyltrimethylammonium chloride.
Claim 7
Dependent Claim
116 words
A drilling mud which comprises: (a) salt water having about 0.1 to about 50 grams of salt per 100 grams of water; and (b) about 0.25 to about 15 lbs/bbl of the acrylamide-based polyampholyte containing low to moderate levels of anionic and cationic groups to increase the viscosity of said drilling mud, said terpolymer containing acrylamide monomer units and having about 1 to about 50 mole % of the charged monomer units, said terpolymer possessing unequal molar ratio of anionic and cationic monomers, said anionic monomer being sodium styrene sulfonate, and said cationic monomer being selected from the group consisting of methacrylamidopropyltrimethylammonium chloride, dimethyldiallylammonium chloride, diethyldiallylammonium chloride, 2-methacryloxy-2-ethyltrimethylammonium chloride, trimethylmethacryloxethylammonium methosulfate, 2-acrylamido-2-methylpropyltrimethylammonium chloride, and vinylbenzyltrimethylammonium chloride.
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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) | 1988-09-09 | 1989-03-11 | 1989-09-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-09-09 | 1993-03-11 | 1993-09-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-09-09 | 1997-03-11 | 1997-09-10 | $7700.00 | Window Closed / Lapsed |