| 摘要 |
A method of reducing the viscosity of invert emulsions and oil-based drilling fluids and well service fluids comprising such emulsions over a broad temperature range is disclosed. The method comprises adding to said invert emulsions of the invention a non-ionic surfactant alone or in combination with a co-thinner having the formula: R''''-(C2H4O)n(C3H6O)m(C4H8O)k-H where R'''' is a saturated or unsaturated, linear or branched, alkyl radical having about 8 to about 24 carbon atoms, n is a number ranging from about 1 to about 10, m is a number ranging from about 0 to about 10, and k is a number ranging from about 0 to about 10. The non-ionic surfactant is a reaction product of ethylene oxide, propylene oxide and/or butylene oxide with C10-22 carboxylic acids or C10-22 carboxylic acid derivatives containing at least in position 9/10 and/or 13/14 structural units of general formula (I) where R1 is a hydrogen atom or an OH group or a group OR2. R2 is an alkyl group of about 1 to about 18 carbon atoms, an alkenyl group of about 2 to about 18 carbons atoms, or a group of the formula (II): R3 is a hydrogen atom, an alkyl group of about 1 to about 21 carbon atoms or an alkylene group or 2 to 21 carbon atoms.
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