US4655942A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Controlled release dispersant for clay-thickened, water-based drilling fluids
Assignee: Mobil Oil AS
•
Filing: 1985-02-01
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Granted: 1987-04-07
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Expires: 2005-02-01
Abstract
Abstract A clay-thickened, water-based drilling fluid composition demonstrating enhanced stability at the elevated temperatures encountered in deep drilling oil and gas recovery operations in described. The drilling fluid composition comprises an aqueous clay dispersion and a dispersing amount of a polymer crosslinked through a polyvalent metal cation.
Inventors
- 👤 Joseph J. Dickert, Jr.
- 👤 Israel J. Heilweil
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 22:48
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/02; C09K8/04; C09K8/14; C09K8/18; C09K8/22; C09K8/24; Y; Y10; Y10S; Y10S507/00; Y10S507/903
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
218 words
A clay-thickened, water-based drilling fluid comprising: (a) an aqueous clay dispersion; and (b) a dispersing amount of a polymer crosslinked through Sn ++ cation, said polymer prior to crosslinking possessing an average molecular weight of from 2,500 to about 1,000,000 and being derived from the polymerization of at least 60 weight percent of ethylenically unsaturated monomer units of the structural formula: ##STR13## wherein R 1 is hydrogen, a phenyl group or an alkyl group of from 1 to 3 carbon atoms; R 2 is a straight or branched chain alkylene group of from about 1 to about 12 carbon atoms or an arylene group of from 6 to about 12 carbon atoms; n is 0 or 1; and X is --NR 3 COR 4 in which R 3 and R 4 each is the same or different and is hydrogen or alkyl of from 1 to about 6 carbon atoms, --COOY' in which Y' is hydrogen or an alkali metal or --CONHZ in which Z is the group --R 5 SO 3 Y in which R 5 is a straight or branched chain alkylene group of from 1 to 12 carbon atoms and Y is hydrogen or an alkali metal, said drilling fluid being stable at down hole temperatures encountered in deep drilling gas and oil recovery operations.
Claim 2
Dependent Claim
218 words
A clay-thickened, water-based drilling fluid comprising: (a) an aqueous clay dispersion; and (b) a dispersing amount of a polymer crosslinked through Sn ++ cation, said polymer prior to crosslinking possessing an average molecular weight of from 2,500 to about 1,000,000 and being derived from the polymerization of at least 60 weight percent of ethylenically unsaturated monomer units of the structural formula: ##STR13## wherein R 1 is hydrogen, a phenyl group or an alkyl group of from 1 to 3 carbon atoms; R 2 is a straight or branched chain alkylene group of from about 1 to about 12 carbon atoms or an arylene group of from 6 to about 12 carbon atoms; n is 0 or 1; and X is --NR 3 COR 4 in which R 3 and R 4 each is the same or different and is hydrogen or alkyl of from 1 to about 6 carbon atoms, --COOY' in which Y' is hydrogen or an alkali metal or --CONHZ in which Z is the group --R 5 SO 3 Y in which R 5 is a straight or branched chain alkylene group of from 1 to 12 carbon atoms and Y is hydrogen or an alkali metal, said drilling fluid being stable at down hole temperatures encountered in deep drilling gas and oil recovery operations.
Claim 3
Dependent Claim
44 words
The drilling fluid of claim 1 wherein said polymer prior to crosslinking contains up to 40 weight percent of copolymerized ethylenically unsaturated monomer units selected from the group consisting of acrylamide, methacrylamide, vinyl sulfonic acid, vinyl benzene sulfonic acid, acrylonitrile, methacrylonitrile and maleic anhydride.
Claim 4
Dependent Claim
20 words
The drilling fluid of claim 1 which is stable at a down hole temperature of at least about 120° C.
Claim 5
Dependent Claim
20 words
The drilling fluid of claim 1 which is stable at a down hole temperature of at least about 150° C.
Claim 6
Dependent Claim
24 words
The drilling fluid of claim 1 which is stable at the temperature encountered at a vertical drilling depth of at least about 15,000 feet.
Claim 7
Dependent Claim
20 words
The drilling fluid of claim 1 wherein R 1 is hydrogen or methyl, n is 0 and X is --COOY'.
Claim 8
Dependent Claim
10 words
The drilling fluid of claim 6 wherein Y' is sodium.
Claim 9
Dependent Claim
20 words
The drilling fluid of claim 1 wherein R 1 is hydrogen or methyl, n is 0 and X is --CONHZ.
Claim 10
Dependent Claim
21 words
The drilling fluid of claim 1 wherein R 5 is --C(CH 3 ) 2 CH 2 -- and Y is sodium.
Claim 11
Dependent Claim
25 words
The drilling fluid of claim 1 wherein the polymer, prior to crosslinking, is prepared from two or more ehtylenically unsaturated monomers of said structural formula.
Claim 12
Dependent Claim
58 words
The drilling fluid of claim 10 wherein the polymer, prior to crosslinking, is prepared by copolymerizing a first momomer in which R 1 is hydrogen or methyl, n is zero and X is --COOY' or --NR 3 COR 4 with a second monomer in which R 1 is hydrogen or methyl, n is 0 and X is --CONHZ.
Claim 13
Dependent Claim
42 words
The drilling fluid of claim 11 wherein Y' is sodium, R 3 is hydrogen and R 4 is methyl in the first monomer and R 5 is --C(CH 3 ) 2 CH 2 -- and Y is sodium in the second monomer.
Claim 14
Dependent Claim
24 words
The drilling fluid of claim 1 wherein the average molecular weight of the polymer, prior to crosslinking, is from about 10,000 to about 100,000.
Claim 15
Dependent Claim
26 words
The drilling fluid of claim 1 containing from about 0.125 lb. to about 6 lb. of crosslinked carboxylate polymer per 42 lb. barrel of drilling fluid.
Claim 16
Dependent Claim
10 words
The drilling fluid of claim 1 containing a weighting material.
Claim 17
Dependent Claim
15 words
The drilling fluid of claim 1 wherein the clay dispersion is prepared with salt water.
Claim 18
Dependent Claim
27 words
A method of deep drilling a well into a subterranean formation which comprises circulating into the well, during drilling, a clay-thickened, water-based drilling fluid of claim 1.
Claim 19
Dependent Claim
27 words
A method of deep drilling a well into a subterranean formation which comprises circulating into the well during drilling, a clay-thickened, water-based drilling fluid of claim 2.
Claim 20
Dependent Claim
20 words
The deep drilling method of claim 17 carried out at a down hole temperature of at least about 120° C.
Claim 21
Dependent Claim
20 words
The deep drilling method of claim 17 carried out at a down hole temperature of at least about 150° C.
Claim 22
Dependent Claim
24 words
The deep drilling method of claim 17 carried out at the temperature encountered at a vertical drilling depth of at least about 15,000 feet.
References Cited (Backward Citations)
US2650905A
Cited
US2718497A
Cited
US2820777A
Cited
US3040820A
Cited
US3035042A
Cited
US3323503A
Cited
US3558545A
Cited
US3472325A
Cited
US3768565A
Cited
US3921733A
Cited
US3948783A
Cited
US3953342A
Cited
US4043921A
Cited
US4055502A
Cited
GB2044321A
Cited
US4309523A
Cited
US4451389A
Cited
US4322301A
Cited
US4425241A
Cited
US4411800A
Cited
US4447339A
Cited
US4457853A
Cited
US4447338A
Cited
US4455240A
Cited
US4442011A
Cited
US4455241A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-04-06 | 1990-10-06 | 1991-04-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-04-06 | 1994-10-06 | 1995-04-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-04-06 | 1998-10-06 | 1999-04-07 | $7700.00 | Window Closed / Lapsed |