Patent ID: 7956014

Claim:
A yield point enhancer for use in oil based drilling muds comprising the product obtained from a process comprising: in a first step, (i) reacting: about one molar equivalent of one or more dicarboxylic fatty acids having a general formula HOOC—R—COOH wherein R is an alkylene group containing from 10 to 50 carbon atoms, with about one molar equivalent of a secondary dialkanolamine having the general formula HO—R′—NH—R′OH wherein R′ is an alkylene group containing from 1 to 6 carbon atoms, at about 150° C. while collecting water and keeping the reaction mixture stirred until about one molar equivalent of water is collected to form an intermediate; and in a second step (ii), reacting, the intermediate with about one third of a molar equivalent of a tertiary trialkanolamine having the general formula N(—R″OH) 3 wherein R″ is an alkylene group containing from 1 to 6 carbon atoms, at 120-150° C. while collecting water and keeping the reaction mixture stirred until about one molar equivalent of water is collected.