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.

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.

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.

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 in the presence of drilling, fracturing and completion fluids carrying oxygen. The imidazoline is an ionic salt or a beatine.

Abstract: Sulfate anions and divalent metal ions in water are removed by treating sulfate-containing water, at a pH of 11-12.5, with aluminum chloride and calcium chloride, optionally together with lime, to form solid ettringite and similar crystalline species. Sulfate is removed as part of the ettringite or ettringite-like materials, but calcium content can be reduced at the same time even though calcium chloride is used as an additive to the treated water. Lime may be used also as a supplemental source of calcium and to help raise the pH. Iron may also be removed by oxidation in a variation of the process. In well treatment, divalent metal ions in flowback fluids can reduce the amount of calcium otherwise necessary to form the solid materials, thus further facilitating recycling of the fluid.

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.

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 in the presence of drilling, fracturing and completion fluids carrying oxygen. The imidazoline is an ionic salt or a beatine.

Abstract: Sulfate anions and divalent metal ions, such as magnesium, strontium and barium, in water are removed by treating the water with polyaluminum chloride, usually together with lime, to form ettringite and similar crystalline species which are readily removable by settling, filtration and the like. Iron is also removed by oxidation in a variation of the process. The process is particularly useful for treating aqueous solutions used in well treatment, where flowback fluids can provide some of the divalent metal ions necessary to form the ettringite-like materials, thus reducing the amount of lime otherwise necessary and further facilitating recycling of the fluid.