Organoclay compositions for drilling fluids useful to provide substantially constant rheology profiles to such fluids over a wide temperature range

A method of providing a substantially constant equivalent circulating density of an oil-based drilling fluid over a temperature range of about 120° F. to about 40° F., comprising adding drilling fluid additive to the drilling fluid, wherein the drilling fluid additive comprises an organoclay composition comprising:

• a phyllosilicate clay;
• and
• a mixture of quaternary ammonium ions, each ion having a formula of [N—R1R2R3R4]+ wherein one or more of R1, R2 and R3 is each a mixture of branched alkyl groups, each branched alkyl group having 12 to 22 total carbon atoms, a linear backbone and one or more C1 to C3 branching alkyl groups each being linked to the linear backbone, wherein within each quaternary ammonium ion and within the mixture of branched alkyl groups, the branching alkyl groups are linked to the linear backbones at different carbon positions along the linear backbones as a distribution;
• and wherein when one or more of R2 and R3 is not a branched alkyl group, R2 and R3 are a first linear alkyl group having 1 to 22 carbon atoms, wherein R4 is selected from the group consisting of a second linear alkyl group having 1 to 6 carbon atoms, an aryl group and combinations thereof.