Method for dispersing aqueous based drilling fluid for drilling subterranean boreholes
AssigneeHalliburton Energy Services, Inc.
InventorsKingsley Ihueze Nzeadibe, Gregory Paul Perez
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Abstract
An inhibitive water-based polymer mud system and method for using the system in drilling and in stabilizing wellbores for use in water sensitive formations as an alternative to oil-based muds or water-based muds comprising ferro-chrome lignosulfonates. The system comprises a fresh water or salt water base thinned or dispersed with a sulfonated acrylic copolymer having a hybrid/graft lignosulfonate multipolymer structure containing carboxylate and sulfonate functional groups with synthetic polymer side chains covalently linked to a base lignosulfonate material, having a molecular weight in the range of about 1,000 to about 15,000, and having a high anionic charge density.
Claims13
A method of thinning an aqueous based drilling fluid for use in drilling a borehole in a subterranean formation, comprising adding to the drilling fluid an additive comprising an acrylic copolymer comprising a hybrid/graft lignosulfonate multipolymer, containing carboxylate and sulfonate functional groups, with synthetic polymer side chains covalently linked to a base lignosulfonate material, and having a molecular weight in the range of 1,000 to 15,000 and a high anionic charge density as indicated by a zeta potential of about 18 to 19 mV.
A method for drilling a borehole in a subterranean formation having water-sensitive formations and temperatures greater than 350° F., said method comprising:
- providing an aqueous based drilling fluid thinned with an additive comprising a sulfonated acrylic copolymer having a hybrid/graft lignosulfonate multipolymer structure containing carboxylate and sulfonate functional groups with synthetic polymer side chains covalently linked to a base lignosulfonate material, wherein the copolymer has a molecular weight in the range of 4000 to 10,000, and has a high anionic charge density as indicated by a zeta potential of about 18 to 19 mV;
- and
- drilling with the drilling fluid in the subterranean formation.
Dependencies are inferred from the claim text.