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US 4,784,778 AGranted
Corrosion inhibiting composition for zinc halide-based clear, high density fluids
AssigneeGreat Lakes Chemical Corporation
InventorCharles C. Shin
Life of this patent
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Abstract
Thio group corrosion inhibitors and aldose group antioxidants when combined provide a synergistic corrosion inhibition system for clear, high density oil and gas completion and workover fluids.
Claims17
A corrosion inhibiting composition adapted for use with clear, high density fluids having application as well completion and workover media comprising:
- about 5-95 parts by weight of a thio group corrosion inhibitor selected from the group consisting of alkali metal and ammonium thioglycolates and thiocyanates, thiourea, mercapto acetic acid and salts thereof, dithiodiglycolic acid, and mixtures thereof;
- and
- about 95-5 parts by weight of an aldose group antioxidant selected from the group consisting of ascorbic acid and salts thereof, gluconic acid, and mixtures of ascorbic acid with gluconic acid.
A corrosion inhibited clear high density fluid for use as a well completion and workover medium comprising:
- a clear aqueous solution of zinc bromide and a calcium halide and, optionally, one or more an alkali metal halides and having a density of about 10 to 20 pounds per gallon;
- about 0.05-5.00 parts per hundred parts by weight of the clear solution of a thio group corrosion inhibitor selected from the group consisting of alkali metal and ammonium thioglycolates and thiocyanates, thiourea, mercapto acetic acid and salts thereof, dithiodiglycolic acid, and mixtures thereof;
- and
- about 95-5 parts by weight of an aldose group antioxidant selected from the group consisting of ascorbic acid and salts thereof, gluconic acid, and mixtures of ascorbic acid with gluconic acid.
1 more element
Dependencies are inferred from the claim text.