IMPROVED AQUEOUS-BASED WELLBORE FLUIDS

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 exists in a liquid state at a temperature below 150°C and which has an ammonium, phosphonium or sulfonium cation containing at least 5 carbon atoms, or a quaternised nitrogen-containing heterocyclic cation containing at least 6 carbon atoms; provided that said salt is not 2- hydroxy-N,N,N-trimethyl ethanaminium acetate; 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.