Tetra Technologies, Inc.

Rosa T Swartwout

Surendra Kumar Mishra

Russell A Fisher

Stephen Stroh

In a method for enhancing the compatibility of a zinc-brine completion fluid with a fracturing fluid, test samples of selected completion fluids are combined with test samples of selected fracturing fluids to form an admixture. The parameters of incompatibility between the completion fluid and the fracturing fluid are analyzed and identified. The parameters or indicia of incompatibility identified can be precipitation, emulsification and/or an increase in viscosity. The zinc brine completion fluid is then blended with additives to remove these parameters of incompatibility. The additives can be selected from a group comprising hydrochloric acid, hydrobromic acid, acetate salts, citrate salts, and surfactants. At the well site, the altered zinc brine completion fluid is pumped in to displace drilling fluids in the wellbore before pumping in fracturing fluid. Additional altered brine completion can follow the fracturing fluid into the wellbore. Commingling of the altered zinc brine completion fluid with fracturing fluid in the wellbore or the formation can occur without substantial damage to the formation.

Method for enhancing the compatibility of a zinc-brine completion fluid

There is provided a method of drilling an oil or gas well, comprising drilling a wellbore into an underground formation in which a drill bit at the lower end of a drill pipe is placed at the bottom of the wellbore; pumping a first drilling fluid into the wellbore; determining the producing zone of the underground formation; and introducing a second drilling fluid into the wellbore through the drill pipe when the borehole is within the producing zone of the underground formation, wherein the second drilling fluid is a high density drill-in fluid, having a composition different from that of the first drilling fluid and including a brine system with at least one dissolved monovalent salt and at least one dissolved divalent salt together with a suspension polymer, said drilling fluid having a density of at least about 1.50 g/cm.sup.3 and a plastic viscosity of less than about 50 lbs/100 ft.sup.2.

Drill-in fluids and drilling methods

A method of converting sodium bromide brine to ammonium bromide brine and optionally to calcium bromide is disclosed. The method involves introducing ammonia and carbon dioxide into the reactant brine, removing a resulting bicarbonate precipitate, driving off any excess ammonium carbonate, and optionally contacting with lime.

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Houston, TX, United States of America

Rosa T Swartwout