US4455241A
Expired / Lapsed
US
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Wellbore fluid
Assignee: Drilling Specialties Co
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Filing: 1982-02-16
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Granted: 1984-06-19
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Expires: 2002-02-16
Abstract
Abstract The water loss properties of well completion and well workover fluids are improved by the addition of an effective amount of at least one adjuvant selected from (1) sodium carbonate with either sodium bicarbonate or an organic polycarboxylic acid or polycarboxylic acid anhydride or (2) sodium bicarbonate alone. In another embodiment, the adjuvants are added to stabilize water loss control agents in wellbore fluids, especially at elevated temperatures.
Inventors
- 👤 Billy L. Swanson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 15:20
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/02; C09K8/04; C09K8/06; E; E21; E21B; E21B21/00; E21B21/003; Y; Y10; Y10S; Y10S507/00; Y10S507/925
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
63 words
A method for producing wellbore fluids which comprises combining aqueous clay-free wellbore fluids having densities ranging from about 11 to about 15 lb/gal with a water-loss improving amount of an additive selected in the group consisting of (a) NaHCO 3 (b) NaHCO 3 and Na 2 CO 3 and (c) Na 2 CO 3 and an organic polycarboxylic acid or polycarboxylic acid anhydride.
Claim 2
Independent Claim
63 words
A method for producing wellbore fluids which comprises combining aqueous clay-free wellbore fluids having densities ranging from about 11 to about 15 lb/gal with a water-loss improving amount of an additive selected in the group consisting of (a) NaHCO 3 (b) NaHCO 3 and Na 2 CO 3 and (c) Na 2 CO 3 and an organic polycarboxylic acid or polycarboxylic acid anhydride.
Claim 3
Dependent Claim
24 words
A method according to claim 1 wherein said additive is NaHCO 3 and said amount is at least about 10 lb/bbl of workover fluid.
Claim 4
Dependent Claim
79 words
A method according to claim 1 wherein said additive is NaHCO 3 and Na 2 CO 3 and said amount ranges from about 8 to about 20 lb/bbl of fluid and the amount of Na 2 CO 3 present in the ranges from about 65 to about 15 wt. % and the amount of NaHCO 3 ranges from about 35 to about 85 wt. % based on the combined weight of Na 2 CO 3 and NaHCO 3 .
Claim 5
Dependent Claim
42 words
A method according to claim 1 wherein said additive is (c) and said amount ranges from about 5 to about 10 lb/bbl and the weight ratio of Na 2 CO 3 to said polycarboxylic acid ranges from about 20:1 to about 5:1.
Claim 6
Dependent Claim
15 words
A method according to claim 1 wherein said wellbore fluid contains a natural polymer viscosifier.
Claim 7
Dependent Claim
18 words
A method according to claim 5 wherein said viscosifier is selected from guar gum, cellulose ethers, and polysaccharides.
Claim 8
Dependent Claim
23 words
A method according to claim 5 wherein said viscosifier is present in amounts ranging from about 0.25 lb/bbl to about 3 lb/bbl fluid.
Claim 9
Dependent Claim
55 words
A wellbore composition comprising an aqueous clay-free wellbore fluid having a density ranging from about 11 to about 15 lb/gal fluid and a water loss stabilizing amount of an additive consisting essentially of (a) NaHCO 3 (b) NaHCO 3 and Na 2 CO 3 and (c) Na 2 CO 3 and an organic polycarboxylic acid.
Claim 10
Dependent Claim
55 words
A wellbore composition comprising an aqueous clay-free wellbore fluid having a density ranging from about 11 to about 15 lb/gal fluid and a water loss stabilizing amount of an additive consisting essentially of (a) NaHCO 3 (b) NaHCO 3 and Na 2 CO 3 and (c) Na 2 CO 3 and an organic polycarboxylic acid.
Claim 11
Dependent Claim
23 words
A composition according to claim 8 wherein said additive is (a) and said amount is at least about ten lb/bbl of workover fluid.
Claim 12
Dependent Claim
73 words
A composition according to claim 8 wherein said additive is (b) and said amount ranges from about 8 to about 20 lb/bbl of fluid and the amount of Na 2 CO 3 present in the ranges from about 65 to about 15 wt. % and the amount of NaHCO 3 ranges from about 35 to about 85 wt. % based on the combined weight of Na 2 CO 3 and NaHCO 3 .
Claim 13
Dependent Claim
42 words
A composition according to claim 8 wherein said additive is (c) and said amount ranges from about 5 to about 10 lb/bbl and the weight ratio of Na 2 CO 3 to said polycarboxylic acid ranges from about 20:1 to about 5:1.
Claim 14
Dependent Claim
36 words
A composition according to claim 8 wherein said wellbore fluid contains (1) an electrolyte selected from water soluble inorganic salts (2) an acid soluble weighting agent (3) a polymeric viscosity additive and (4) a suspending agent.
Claim 15
Dependent Claim
25 words
A composition according to claim 12 wherein (1) is NaCl (2) is CaCO 3 (3) is carboxymethyl cellulose or carboxymethylhydroxyethyl cellulose and (4) is asbestos.
Claim 16
Dependent Claim
24 words
A composition according to claim 11 wherein said polycarboxylic acid is tartaric acid, citric acid, oxalic acid, tannic acid, adipic acid, or phthalic anhydride.
Claim 17
Dependent Claim
15 words
A composition according to claim 8 wherein said wellbore fluid contains a natural polymer viscosifier.
Claim 18
Dependent Claim
18 words
A composition according to claim 15 wherein said viscosifier is selected from guar gum, cellulose ethers, and polysaccharides.
Claim 19
Dependent Claim
23 words
A composition according to claim 16 wherein said viscosifier is present in amounts ranging from about 0.25 lb/bbl to about 3 lb/bbl fluid.
Claim 20
Dependent Claim
13 words
A composition according to claim 8 wherein said wellbore fluid is a brine.
Claim 21
Dependent Claim
15 words
A composition according to claim 15 wherein said viscosifier is carboxymethyl cellulose or carboxymethylhydroxyethyl cellulose.
Claim 22
Dependent Claim
18 words
A composition according to claim 19 wherein said additive is NaHCO 3 and Na 2 CO 3 .
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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) | 1987-06-19 | 1987-12-19 | 1988-06-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-06-19 | 1991-12-19 | 1992-06-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-06-19 | 1995-12-19 | 1996-06-19 | $7700.00 | Window Closed / Lapsed |