Shale hydration inhibition agent and method of use

Abstract From the Canadian patent

A water-base fluid for use in drilling cementing, workover, fracturing and , abandonment of subterranean wells through a formation containing shale which swells in the presence of water. In one illustrative embodiment the drilling , fluid is composed of an aqueous based continuous phase a weighting agent, and , a shale hydration inhibition agent. The shale hydration inhibition agent should have the general formula (I): in which R and R' independently selected from hydrogen, methyl, ethyl or propyl and X has a value from 1 to 6. The , shale hydration inhibition agent is present in sufficient concentration to substantially reduce the swelling of shale drilling cuttings upon contact with …