METHOD OF STABILISING CLAY OR SHALE

摘要

A method of reducing the swelling of shale or clay encountered in a wellbore, the method comprising introducing into the wellbore a composition comprising: (a) a continuous aqueous phase; (b) a source of borate ions; (c) a source of ions selected from the group consisting of alkali metal ions, alkaline earth metal ions and ammonium ions; and (d) optionally a source of at least one sugar selected from the group consisting of monosaccharides and oligosaccharides having from 2 to 4 saccharide groups.