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US4502964A Expired / Lapsed US ⏱️ 0.0 years remaining

Terpolymers for use as high temperature fluid loss additive and rheology stabilizer for high pressure, high temperature oil well drilling fluids

Assignee: Nalco Exxon Energy Chemicals LP
•
Filing: 1983-09-09
•
Granted: 1985-03-05
•
Expires: 2003-09-09
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Abstract

Abstract Novel water-soluble terpolymers comprising: ______________________________________ Ingredients Mole % ______________________________________ 2-acrylamido-2-methylpropane- 51-59 sulfonic acid, sodium salt (AMPS) N,N--dimethylacrylamide 6-28 acrylonitrile 20-35 ______________________________________ These terpolymers provide high temperature fluid loss additives and rheology stabilizers for high calcium-containing brine clay drilling fluids.

Inventors

  • 👤 David M. Giddings
  • 👤 Donald G. Ries
  • 👤 Allen R. Syrinek

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-02 11:29
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; C08F220/52; C08F220/54; C08F220/58; C08F220/585

Claims Analysis

Total Claims: 4
Claim 1
Independent Claim 61 words
A method of improving high temperature fluid loss and rheology stabilization of high calcium brine clay-containing oil well drilling fluids which comprises adding thereto a stabilizing amount of a water-soluble terpolymer comprising: ______________________________________ Ingredients Mole % ______________________________________ 2-acrylamido-2-methylpropane- 51-59 sulfonic acid, sodium salt N,N--dimethylacrylamide 6-28 acrylonitrile 20-35 ______________________________________ and said terpolymer being further characterized as having a molecular weight below 1,000,000.
Claim 2
Independent Claim 61 words
A method of improving high temperature fluid loss and rheology stabilization of high calcium brine clay-containing oil well drilling fluids which comprises adding thereto a stabilizing amount of a water-soluble terpolymer comprising: ______________________________________ Ingredients Mole % ______________________________________ 2-acrylamido-2-methylpropane- 51-59 sulfonic acid, sodium salt N,N--dimethylacrylamide 6-28 acrylonitrile 20-35 ______________________________________ and said terpolymer being further characterized as having a molecular weight below 1,000,000.
Claim 3
Independent Claim 61 words
A method of improving high temperature fluid loss and rheology stabilization of high calcium brine clay-containing oil well drilling fluids which comprises adding thereto a stabilizing amount of a water-soluble terpolymer comprising: ______________________________________ Ingredients Mole % ______________________________________ 2-acrylamido-2-methylpropane- 53.5 sulfonic acid, sodium salt N,N--dimethylacrylamide 16.6 acrylonitrile 29.8 ______________________________________ and said terpolymer being further characterized as having a molecular weight below 1,000,000.
Claim 4
Independent Claim 61 words
A method of improving high temperature fluid loss and rheology stabilization of high calcium brine clay-containing oil well drilling fluids which comprises adding thereto a stabilizing amount of a water-soluble terpolymer comprising: ______________________________________ Ingredients Mole % ______________________________________ 2-acrylamido-2-methylpropane- 53.5 sulfonic acid, sodium salt N,N--dimethylacrylamide 16.6 acrylonitrile 29.8 ______________________________________ and said terpolymer being further characterized as having a molecular weight below 1,000,000.

References Cited (Backward Citations)

US2718497A Cited
GB1197323A Cited
US3629101A Cited
US3929741A Cited
US4048077A Cited
US4357245A Cited
US4404111A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1988-03-04 1988-09-03 1989-03-05 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1992-03-04 1992-09-03 1993-03-05 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1996-03-04 1996-09-03 1997-03-05 $7700.00 Window Closed / Lapsed

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