METHOD AND COMPOSITIONS FOR RHEOLOGY MODIFICATION OF AQUEOUS SOLUBLE SALT SOLUTIONS
A method of making a rheology modified aqueous salt solution includes adding thereto, a non-hydratable clay, as defined, and at least one compound capable of contributing, in solution, a divalent metal cation and a trivalent metal cation; and then adjusting the pH to a specific range. A dry composition comprising at least one compound capable of contributing the designated cations and, optionally, the non-hydratable clay is also disclosed. This invention is particularly applicable to drilling fluids, and more particulady to such fluids used in coastal and deepsea drillsites where the presence of salinity has been known to significantly reduce the effectiveness of clays as thickening agents.