ALEXANDRIA, Va., July 3 -- United States Patent no. 12,344,793, issued on July 1.
"Divalent-brine-based high density drilling fluids" was invented by Hui Zhou (Houston), Preston Andrew May (Houston), Ayten Rady (Houston) and Mohamed Metwally (Houston).
According to the abstract* released by the U.S. Patent & Trademark Office: "Drilling fluids and methods for drilling a wellbore. An example drilling fluid is a divalent brine aqueous base fluid having at least one dissolved divalent zinc salt and also a polymeric additive that is a cross-linked copolymer comprising a first comonomer of 2-acrylamido-2-methylpropanesulfonic acid in a first comonomer concentration of at least 50 mol % of the copolymer; wherein the polymeric additive additional...