Water-based drilling fluids using latex additives

A water-based drilling fluid comprising:

• a) a polymer latex;
• b) a precipitating agent;
• c) a surfactant;
• and d) water.

A water-based drilling fluid comprising:

• a) from about 1 to about 10 volume % of a polymer latex selected from the group consisting of polymethyl methacrylate, polyethylene, carboxylated styrene/butadiene copolymer, sulfonated styrene/butadiene copolymer, polyvinylacetate copolymer, polyvinyl acetate/vinyl chloride/ethylene copolymer, polyvinyl acetate/ethylene copolymer, natural latex, polyisoprene, polydimethylsiloxane, and mixtures thereof;
• b) from about 0.25 to about 20 lb/bbl of a precipitating agent selected from the group consisting of silicates, aluminum complexes, and mixtures thereof;
• c) at least 1 wt. % of a salt selected from the group consisting of calcium chloride, sodium chloride, potassium chloride, magnesium chloride, calcium bromide, sodium bromide, potassium bromide, calcium nitrate, sodium formate, potassium formate, cesium formate, and mixtures thereof;
• d) from about 0.005 to about 2 vol. % of a surfactant selected from the group consisting of betaines, alkali metal alkylene acetates, sultaines, ether carboxylates, and mixtures thereof;
• and e) water making up the balance, where the proportions are based on the total water-based drilling fluid.

A method of inhibiting borehole wall invasion when drilling with a water-based drilling fluid in a subterranean formation, the method comprising:

• a) providing a water-based drilling fluid comprising:
• i) a polymer latex capable of providing a deformable latex seal on at least a portion of a subterranean formation;
• and ii) water;
• and b) circulating the water-based drilling fluid in contact with a borehole wall.

A method of inhibiting borehole wall invasion when drilling with a water-based drilling fluid in a subterranean formation, the method comprising:

• a) providing a water-based drilling fluid comprising:
• i) a polymer latex;
• ii) a precipitating agent;
• and iii) water;
• and b) circulating the water-based drilling fluid in contact with a borehole wall.

A method of inhibiting borehole wall invasion when drilling with a water-based drilling fluid in a subterranean formation, the method comprising:

• a) providing a water-based drilling fluid comprising:
• i) a polymer latex;
• ii) a precipitating agent;
• iii) a surfactant;
• and iv) water;
• and b) circulating the water-based drilling fluid in contact with a borehole wall.

A method of inhibiting borehole wall invasion when drilling with a water-based drilling fluid in a subterranean formation, the method comprising:

• a) providing a water-based drilling fluid comprising:
• i) from about 0.1 to about 10 vol. % of a polymer latex selected from the group consisting of polymethyl methacrylate, polyethylene, carboxylated styrene/butadiene copolymer, sulfonated styrene/butadiene copolymer, polyvinylacetate copolymer, polyvinyl acetate/vinyl chloride/ethylene copolymer, polyvinyl acetate/ethylene copolymer, natural latex, polyisoprene, polydimethylsiloxane, and mixtures thereof;
• ii) from about 0.25 to about 20 lb/bbl of a precipitating agent selected from the group consisting of silicates, aluminum complexes, ether carboxylates, and mixtures thereof;
• iii) at least 1 wt. % of a salt selected from the group consisting of calcium chloride, sodium chloride, potassium chloride, magnesium chloride, calcium bromide, sodium bromide, potassium bromide, calcium nitrate, sodium formate, potassium formate, cesium formate, and mixtures thereof;
• iv) from about 0.005 to about 2 vol. % of a surfactant selected from the group consisting of betaines, alkali metal alkylene acetates, sultaines, ether carboxylates, and mixtures thereof;
• and v) water making up the balance, where the proportions are based on the total water-based drilling fluid;
• and b) circulating the water-based drilling fluid in contact with a borehole wall.

A method of inhibiting borehole wall invasion when drilling with a water-based drilling fluid in a subterranean formation, the method comprising:

• a) providing a water-based drilling fluid comprising:
• i) from about 0.1 to about 10 vol. % of a sulfonated styrene/butadiene copolymer;
• ii) from about 0.25 to about 20 lb/bbl of a precipitating agent selected from the group consisting of silicates, aluminum complexes, ether carboxylates, and mixtures thereof;
• and iii) water making up the balance, where the proportions are based on the total water-based drilling fluid;
• and b) circulating the water-based drilling fluid in contact with a borehole wall.

A method of inhibiting borehole wall invasion when drilling with a water-based drilling fluid in a subterranean formation to reduce drilling fluid loss while drilling in depleted sands, the method comprising:

• a) providing a water-based drilling fluid comprising:
• i) from about 0.1 to about 10 vol. % of a sulfonated styrene/butadiene copolymer;
• and ii) water making up the balance, where the proportions are based on the total water-based drilling fluid;
• and b) circulating the water-based drilling fluid in contact with a borehole wall.

A method of inhibiting borehole wall invasion when drilling with a water-based drilling fluid in a subterranean formation to reduce drilling fluid loss while drilling in depleted sands, the method comprising:

• a) providing a water-based drilling fluid comprising:
• i) from about 0.1 to about 10 vol. % of a carboxylated styrene/butadiene copolymer;
• ii) from about 0.005 to about 2 vol. % of a surfactant selected from the group consisting of betaines, alkali metal alkylene acetates, sultaines, ether carboxylates, and mixtures thereof;
• and water making up the balance, where the proportions are based on the total water-based drilling fluid;
• and b) circulating the water-based drilling fluid in contact with a borehole wall.