Emulsifier compositions for invert emulsion fluids and methods of using the same

Abstract

Drilling fluid compositions include invert emulsion fluids having an oleaginous phase, an aqueous phase, and an emulsifier composition that includes an ethoxylated alcohol compound and a polyaminated fatty acid compound. The ethoxylated alcohol compound has the formula R1—(OCH2CH2)n—OH, where R1 is a hydrocarbyl group having from 8 to 22 carbon atoms and n is from 1 to 8. The ethoxylated alcohol compound has a Hydrophilic-Lipophilic Balance (HLB) of less than or equal to 6. The polyaminated fatty acid compound has the formula R2—CO—NH—CH2—CH2—N(COR2)—CH2—CH2—NH—CO—R3, where R2 is a hydrocarbyl group having from 1 to 20 carbon atoms and R3 is a hydrocarbyl group having from 1 to 10 carbon atoms or an alkylene carboxylate group having formula —R4—COOH, where R4 is a saturated or unsaturated hydrocarbylene having from 1 to 10 carbon atoms. Methods of drilling wells include operating a drill in a wellbore in the presence of drilling fluid compositions.

Dependencies are inferred from the claim text.