Compositions for drilling fluids useful to provide flat temperature rheology to such fluids over a wide temperature range and drilling fluids containing such compositions

Abstract

The invention is of oil-based drilling fluids including invert emulsion fluids that are able to maintain a relatively consistent rheological profile over a wide temperature range. The invention also includes new additives that enable the preparation of drilling fluids with viscosities that are less affected by temperature over a temperature range from less than about 40° F. to more than about 250° F. compared to conventional fluids. These additives are based on reaction products of polyamines and carboxylic acids with two or more carboxylic moieties combined with alkoxylated amines and fatty acid amides. In addition, this invention permits the use of reduced amounts of organoclay rheological additives in drilling fluids.

Dependencies are inferred from the claim text.