Patent ID: 7879768

Claim:
A drilling fluid composition comprising: (a) one or more hydrophobically associating tetra-polymers, wherein the tetra-polymers comprise one type of monomer units selected from each of the following groups i)-iv): i) vinyl monomers comprising at least one amide group; ii) vinyl monomers comprising at least one carboxylic acid group or carboxylate group; iii) vinyl monomers comprising at least one of a quaternary nitrogen atom, a quaternary nitrogen atom with an alkyl sulfonate group, a quaternary nitrogen atom with a carboxylic acid group or a quaternary nitrogen atom with a carboxylate group; and iv) vinyl monomers comprising a hydrophobic group, wherein the vinyl comprising a hydrophobic group is a C 8-20 alkyl methacrylate ester; (b) one or more water wetting agents; (c) a water continuous phase comprising clay minerals; and (d) one or more conventional drilling fluid additives, wherein at least one of the conventional drilling fluid additives is a defoaming agent, and wherein the hydrophobically associating tetra-polymers are present in an amount effective to inhibit sticking and/or dispersion of bitumen during bitumen recovery from oil sands.