US4626362A
Expired / Lapsed
US
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Additive systems for control of fluid loss in aqueous drilling fluids at high temperatures
Assignee: Mobil Oil AS
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Filing: 1985-04-11
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Granted: 1986-12-02
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Expires: 2005-04-11
Abstract
Abstract Various water-soluble additives, either alone or in various combinations, for use in water-based clay drilling fluids. The additives are an acrylate polymer, an acrylate propylene glycol copolymer and three structurally different sulfonate amide polymers. One of the sulfonate amide polymers is a terpolymer consisting of a random distribution of units of the formulae <IMAGE> <IMAGE> <IMAGE> wherein R1 and R2 are the same or different and each is hydrogen, methyl, or ethyl, and X+ is a cation. A second sulfonate amide polymer is a copolymer consisting only of a random distribution of units (a) and (b). The third sulfonate amide polymer is a copolymer consisting of 2-acrylamido-2-methyl propane sulfonic acid and acrylamide. The acrylate polymer is of the formula <IMAGE> while the acrylate propylene glycol copolymer is of the formula <IMAGE> Drilling operations using a drilling fluid containing these compositions can be carried out at pH levels from about 8 to 11.5 and at temperatures up to about 220 DEG C. The use of the above compositions in a water-based clay drilling fluid results in a reduced fluid loss rate.
Inventors
- 👤 Joseph J. Dickert, Jr.
- 👤 Israel J. Heilweil
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 19:59
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/02; C09K8/04; C09K8/14; C09K8/18; C09K8/22; C09K8/24
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
144 words
A water-based clay drilling fluid containing from 0.25 lbs./bbl. to 6 lbs./bbl. of (A) sulfonate amide polymer 2, a water-soluble sulfonate amide copolymer, having a molecular weight of about 200,000 to 2 million and consisting of a random distribution of units of the formulae ##STR16## in a proportion of 60 wt.% to 80 wt.% of the weight of the copolymer, and ##STR17## in a proportion of 20 wt.% to 40 wt.% of the weight of the copolymer, wherein R 1 and R 2 are the same or different and each is hydrogen, methyl, or ethyl, and X + is a cation, and (B) 0.25 lbs./bbl. to 6 lbs./bbl. of an acrylate polymer of the formula ##STR18## wherein said acrylate polymer has a molecular weight less than 50,000, and wherein the weight ratio of said sulfonate amide copolymer to said acrylate polymer is about 3:1.
Claim 2
Dependent Claim
144 words
A water-based clay drilling fluid containing from 0.25 lbs./bbl. to 6 lbs./bbl. of (A) sulfonate amide polymer 2, a water-soluble sulfonate amide copolymer, having a molecular weight of about 200,000 to 2 million and consisting of a random distribution of units of the formulae ##STR16## in a proportion of 60 wt.% to 80 wt.% of the weight of the copolymer, and ##STR17## in a proportion of 20 wt.% to 40 wt.% of the weight of the copolymer, wherein R 1 and R 2 are the same or different and each is hydrogen, methyl, or ethyl, and X + is a cation, and (B) 0.25 lbs./bbl. to 6 lbs./bbl. of an acrylate polymer of the formula ##STR18## wherein said acrylate polymer has a molecular weight less than 50,000, and wherein the weight ratio of said sulfonate amide copolymer to said acrylate polymer is about 3:1.
Claim 3
Dependent Claim
145 words
A water-based clay drilling fluid containing from 0.25 lbs./bbl. to 6 lbs./bbl. of (A) sulfonate amide polymer 2, a water-soluble copolymer, having a molecular weight of about 200,000 to 2 million and consisting of a random distribution of units of the formulae ##STR19## in a proportion of 60 wt.% to 80 wt.% of the weight of the copolymer, and ##STR20## in a proportion of 20 wt.% to 40 wt.% of the weight of the copolymer, and wherein R 1 and R 2 are the same or different and each is hydrogen, methyl, or ethyl, and X + is a cation, and (B) 0.25 lbs./bbl. to 6 lbs./bbl. of a water-soluble acrylate propylene glycol copolymer of the formula ##STR21## having a molecular weight of less than 50,000, and wherein the weight ratio of said sulfonate amide copolymer to said acrylate propylene glycol copolymer is about 3:1.
Claim 4
Dependent Claim
145 words
A water-based clay drilling fluid containing from 0.25 lbs./bbl. to 6 lbs./bbl. of (A) sulfonate amide polymer 2, a water-soluble copolymer, having a molecular weight of about 200,000 to 2 million and consisting of a random distribution of units of the formulae ##STR19## in a proportion of 60 wt.% to 80 wt.% of the weight of the copolymer, and ##STR20## in a proportion of 20 wt.% to 40 wt.% of the weight of the copolymer, and wherein R 1 and R 2 are the same or different and each is hydrogen, methyl, or ethyl, and X + is a cation, and (B) 0.25 lbs./bbl. to 6 lbs./bbl. of a water-soluble acrylate propylene glycol copolymer of the formula ##STR21## having a molecular weight of less than 50,000, and wherein the weight ratio of said sulfonate amide copolymer to said acrylate propylene glycol copolymer is about 3:1.
Claim 5
Dependent Claim
158 words
A water-based clay drilling fluid containing from 0.25 lbs./bbl. to 6 lbs./bbl. of (A) sulfonate amide polymer 1, a water-soluble terpolymer, having a molecular weight of about 200,000 to 2 million and consisting of a random distribution of units of the formulae ##STR22## in a proportion of 35 wt.% to 70 wt.% of the weight of the terpolymer, ##STR23## in a proportion of 15 wt.% to 35 wt.% of the weight of the terpolymer, and ##STR24## in a proportion of 10 wt.% to 30 wt.% of the terpolymer, wherein R 1 and R 2 are the same or different and each is hydrogen, methyl, or ethyl, and X + is a cation, and (B) from 0.25 lbs./bbl. to 6 lbs./bbl. of a water-soluble acrylate propylene glycol copolymer of the formula ##STR25## having a molecular weight of less than 50,000, and wherein the weight ratio of said sulfonate amide terpolymer to said acrylate propylene glycol copolymer is about 3:1.
Claim 6
Dependent Claim
158 words
A water-based clay drilling fluid containing from 0.25 lbs./bbl. to 6 lbs./bbl. of (A) sulfonate amide polymer 1, a water-soluble terpolymer, having a molecular weight of about 200,000 to 2 million and consisting of a random distribution of units of the formulae ##STR22## in a proportion of 35 wt.% to 70 wt.% of the weight of the terpolymer, ##STR23## in a proportion of 15 wt.% to 35 wt.% of the weight of the terpolymer, and ##STR24## in a proportion of 10 wt.% to 30 wt.% of the terpolymer, wherein R 1 and R 2 are the same or different and each is hydrogen, methyl, or ethyl, and X + is a cation, and (B) from 0.25 lbs./bbl. to 6 lbs./bbl. of a water-soluble acrylate propylene glycol copolymer of the formula ##STR25## having a molecular weight of less than 50,000, and wherein the weight ratio of said sulfonate amide terpolymer to said acrylate propylene glycol copolymer is about 3:1.
Claim 7
Dependent Claim
66 words
In a method of drilling a well wherein a drilling fluid is circulated in the well while drilling at a temperature up to about 220° C., the improvement of employing as said drilling fluid an aqueous clay base drilling fluid having a pH from 8 to 11.5 which contains the composition of any one of claims 1, 2 or 3 as a fluid loss reducing agent.
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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) | 1989-12-01 | 1990-06-02 | 1990-12-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-12-01 | 1994-06-02 | 1994-12-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-12-01 | 1998-06-02 | 1998-12-02 | $7700.00 | Window Closed / Lapsed |