| abstract |
A wellbore fluid may include an oleaginous external phase, a non-oleaginous internal phase and a reaction product of a capping agent with a base emulfisifer, the base emulsifier being a reaction product of a fatty acid and a hydrophilic compound having at least two reactive hydrophilic functional groups, the capping agent being selected from the group consisting of a polycarboxylic acid, anhydride, urea, isocyanate, alpha-halocarboxylic acid, oxirane, cyclic diester, and cyclic sulfonate ester. |