Abstract: Wellbore fluids may contain alkyl amine and cyclic organic acid complexes capable of controlling hydration in swellable formations such as shale- and clay-containing formations. Further, methods of drilling may utilize wellbore fluids containing a base fluid and a complex of alkyl amine and a cyclic organic acid.

Abstract: Wellbore fluids may contain alkyl amine and cyclic organic acid complexes capable of controlling hydration in swellable formations such as shale- and clay-containing formations. Further, methods of drilling may utilize wellbore fluids containing a base fluid and a complex of alkyl amine and a cyclic organic acid.

Abstract: A water-base drilling fluid for use in drilling wells through a formation containing a shale which swells in the presence of water. The drilling fluid preferably includes: an aqueous based continuous phase, a weight material, and a shale hydration inhibition agent having the formula: H2N—R—{OR?}x—Y.[H+B?]d in which R and R? are alkylene groups having 1 to 6 carbon atom and x is a value from about 1 to about 25. The Y group should be an amine or alkoxy group, preferably a primary amine or a methoxy group. The acid H+B? is a protic acid selected from the group consisting of inorganic acids and organic acids, illustrative examples of which include: hydrochloric, hydrobromic, sulfuric, phosphoric, nitric, boric, perchloric, formic, acetic, halogenated acetic, propionic, butyric, maleic, fumeric, glycolic, lactic, citric and combinations of these. The shale hydration inhibition agent should be present in sufficient concentration to reduce the swelling of the shale.

Abstract: A water-base drilling fluid for use in drilling wells through a formation containing a shale which swells in the presence of water.