IMPROVED AQUEOUS-BASED WELLBORE FLUIDS FOR USE TO STABILISE CLAY-CONTAINING FORMATION

摘要

The invention provides a wellbore fluid which comprises an aqueous continuous phase and, dissolved in said aqueous continuous phase, at least one salt which has an ammonium, phosphonium or sulfonium cation containing at least 5 carbon atoms, or a quatemised nitrogen-containing heterocyclic cation containing at least 6 carbon atoms, and a method of carrying out a wellbore operation, which comprises introducing into a wellbore in a clay-containing formation, a wellbore fluid according to the invention. The described salts are effective shale inhibitors.