Method of improving rock hardness in subterranean geologic formation by tripotassium phosphate

Abstract

A method of improving rock hardness in a subterranean geologic formation includes injecting a solution including a phosphate salt through a borehole into the subterranean geologic formation at a temperature of 50-90° C. and a pressure of 600-2000 psi, wherein the solution has a pH of 4 to 14 and a phosphate concentration of 0.5-2 mol/L, and the phosphate salt includes PO43−, followed by saturating rocks in the subterranean geologic formation with the solution for a duration of 1-24 hours, wherein the rocks include Austin chalk (AC), Indiana limestone (IL) or both. The method then includes injecting a liquid fractionating composition through the borehole into the subterranean geologic formation at a pressure of at least 1,000 psi to fracture the rocks in the subterranean geologic formation.

Dependencies are inferred from the claim text.