Method for forming channels of high fluid conductivity in formation parts around a borehole

Abstract From the Canadian patent

A method for forming channels of high fluid conductivity in relatively hard acid-soluble formation parts around a borehole, said method comprising the sequential steps of: 1) installing a casing in the well, and introducing in the wall of the casing a plurality of perforations arranged over at least part of said well where facing the formation;, 2) inducing in the formation a fracture containing a viscous fluid with propping agent at a fluid pressure at which the fracture is kept open;, 3) injecting an aqueous acid solution through the perforations into the fracture at a pressure at which the fracture remains open, the viscosity ratio between the viscous fluid and the acid solution being …