Oil-based emulsifier system comprises superamide, used in stabilization of water-in-oil drilling muds for use at high temperatures and pressures

摘要

An emulsifier system ensures good stability of a water-in -oil composition in high temperature/pressure conditions, up to 200 deg C. An oil-based drilling fluid stable at high temperatures, which non-toxic and particularly adaptable to high pressure/high temperature drilling comprises an emulsifier system consisting of a superamide (alkoxylated, polyalkoxylated or non-oxylated) conforming to either general formulae (I) or (II). (R1-CON(R2)-CH2CHR3-O-(CHR4-CHR5O)m-(CH2CH2O)n)p X (I) R1-CON-(CH2CHR3-O-(CHR4-CHR5O)m-(CH2CH2O)nX)2 (II) R1 = 7-30C hydrocarbyl (optionally unsaturated an optionally with an OH group); R2 = H or 1-4C hydrocarbyl; R3 = H or 1-4C hydrocarbyl; R4 and R5 = H or 1-2C alkyl, on condition that at least one radical is H; X = H, 1-6C hydrocarbyl, phosphate, carboxylate, sulfate or sulfonate; m = 0-20; n = 0-50; and p = 1 or 2, depending on X. An Independent claim is also included for the use of the fluid in oil well drilling operations.