Constraining pyrite activity in shale
AssigneeSmart Chemical Services, LP
InventorsKevin W. Smith, Jeffrey Snider, Jimmy Poindexter
Life of this patent
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Abstract
Degeneration of shale caused by oxygen in aqueous drilling, fracturing and completion fluids is minimized by introducing imidazolines modified so that they will be attracted efficiently to pyrites in the shale, thereby forming a protective coating on the pyrites. Inhibiting oxidation of the pyrites sharply reduces physical degradation of the shale, and the generation of undesirable oxides, in the presence of drilling, fracturing and completion fluids carrying oxygen. The imidazoline is an ionic salt of a monocarboxylic acid.
Claims11
Method of inhibiting the oxidation of iron pyrite present in shale by free oxygen in an aqueous well treatment fluid containing free oxygen comprising (1) adding to said well treatment fluid an ionic salt derived from (a) an imidazoline of the formula
- where R1 is H or a linear alkyl, or monounsaturated or diunsaturated alkyl or alkenyl group of 1-22 carbon atoms, R2 is —(CH2CH2NH)nCH2CH2NH2 and n is 0-5, and (b) a linear monocarboxylic acid having from 1 to 22 carbon atoms in a molar ratio of (a) to (b) of 1:10 to 10:1, and (2) contacting said shale with said well treatment fluid.
Dependencies are inferred from the claim text.