High performance water based drilling mud and method of use

A water based drilling fluid for use in drilling a subterranean well through a subterranean formation that swells in the presence of water, the drilling fluid comprising:

• an aqueous based continuous phase;
• a weight material
• a shale hydration inhibition agent selected from the group:
• 14
• 15
• wherein R and R′ are independently selected alkylene groups having 2 to 4 carbon atoms and mixtures thereof, and
• wherein the shale hydration inhibition agent is present in sufficient concentration to reduce the swelling of the subterranean formation in the presence of water.

A water based drilling fluid for use in drilling a subterranean well through a subterranean formation that swells in the presence of water, the drilling fluid comprising:

• an aqueous based continuous phase;
• a weight material
• a shale hydration inhibition agent that is the product of the reaction of an alkylene oxide with an oxyalkyldiamine having the formula
• H2N—Y—[OY′]x—NH2
• wherein Y and Y′ are alkyl groups having 1 to 6 carbon atoms and x is a value from about 1 to about 10.
• and wherein the shale hydration inhibition agent is present in sufficient concentration to reduce the swelling of the subterranean formation in the presence of water.

A method of forming a subterranean well, the method comprising

• drilling the subterranean well with a rotary drill bit and a drilling fluid;
• said drilling fluid including:
• an aqueous based continuous phase and
• a shale hydration inhibition agent that is the product of the reaction of an alkylene oxide with a oxyalkyldiamine having the formula
• H2N—Y—[OY′]x—NH2
• wherein Y and Y′ are alkyl groups having 1 to 6 carbon atoms and x is a value from about 1 to about 10.
• and wherein the shale hydration inhibition agent is present in sufficient concentration to reduce the swelling of shale clay encountered during the drilling of the subterranean well.

A method of reducing the swelling of shale clay encountered during the drilling of a subterranean well, the method comprising:

• circulating in the subterranean well a water-base drilling fluid including:
• an aqueous based continuous phase and
• a shale hydration inhibition agent that is the product of the reaction of an alkylene oxide with a oxyalkyldiamine having the formula
• H2N—Y—[OY′]x—NH2
• wherein Y and Y′ are alkyl groups having 1 to 6 carbon atoms and x is a value from about 1 to about 10
• and wherein the shale hydration inhibition agent is present in sufficient concentration to reduce the swelling of the clay.

A drilling fluid for use in drilling subterranean wells, said fluid comprising:

• an aqueous based continuous phase,
• a viscosifying agent, and
• a shale hydration inhibition agent that is the product of the reaction of an alkylene oxide with a oxyalkyldiamine having the formula
• H2N—Y—[OY′]x—NH2
• wherein Y and Y′ are alkylene groups having 1 to 6 carbon atoms and x is a value from about 1 to about 10 and wherein the shale hydration inhibition agent is present in sufficient concentration to reduce the swelling of shale clay.

A fluid for use in subterranean wells, said fluid comprising:

• an aqueous based continuous phase,
• a viscosifying agent, and
• a shale hydration inhibition agent that is the product of the reaction of an alkylene oxide with a oxyalkyldiamine having the formula
• H2N—Y—[OY′]x—NH2
• wherein Y and Y′ are alkyl groups having 1 to 6 carbon atoms and x is a value from about 1 to about 10 and wherein the shale hydration inhibition agent is present in sufficient concentration to reduce the swelling of shale clay.