	US 12,258,515 B2
	Invert emulsifier for use in invert emulsion drilling fluids
Arvind Patel, Sugarland, TX (US); Anil Kumar Singh, Mumbai (IN); Sakshi Indulkar, Mumbai (IN); Vivek Gupta, Mumbai (IN); Nikhil Bidwai, Mumbai (IN); Kartiki Dewalkar, Mumbai (IN); and Vijay Kshirsagar, Mumbai (IN)
Assigned to Gumpro Drilling Fluids PVT. LTD, Maharashtra (IN)
Filed by Gumpro Drilling Fluids PVT.LTD, Mumbai (IN)
Filed on Sep. 15, 2021, as Appl. No. 17/476,042.
Claims priority of application No. 202021040521 (IN), filed on Sep. 18, 2020.
Prior Publication US 2022/0089932 A1, Mar. 24, 2022
Int. Cl. C09K 8/36 (2006.01)

CPC C09K 8/36 (2013.01)

22 Claims

1. An invert emulsion drilling fluid comprising:

a) a hydrocarbon continuous phase that is essentially free of esters;

b) an aqueous brine dispersed phase;

c) an alkalinity agent; and

d) a zwitterionic imidazoline invert emulsifier, said emulsifier being oil soluble, and is a reaction product of a fatty acid, a polyalkylene polyamine and an unsaturated monocarboxylic acid and having the formula:

wherein R1 is an alkyl radical derived from the fatty acid;

R2 is a NH₂, NHCORI, OH, polyalkylene polyamine, or a mixture thereof;

R3 is an alkyl radical derived from the unsaturated mono-carboxylic acid containing 3-8 carbon atoms; and

wherein the zwitterionic imidazole invert emulsifier is in a concentration in the range of about 2-12 lbs/bbl of the drilling fluid.