A method for preventing the formation of calcium carboxylate deposits in the dewatering process for crude oil/water streams

摘要

The invention relates to the use of compounds comprising three hydrophobic groups as additives to a stream of crude oil containing carboxylic acids, in particular naphthenic acids, and salt water, toprevent the formation of calcium carboxylates when the fluid is exposed to shear forces. Preferably, the compounds are added to a crude oil/water stream containing organic acids and Ca2+ions at a point between the well and the pressure reduction valve in the crude oil receiving station.The compounds have the formula (l) wherein hydrophobic groups R, R', and R" are, independently, an optionally substituted hydrocarbyl group or an optionally substituted aryl group having 4- 22 carbon atoms; X is N, P=O or CR''', wherein R''' is H or a Cl-C4 alkyl group; Y is C=O or CH2; a, a', a" b, b' and b" each independently are 0 or 1, the ubscript 0-1 meaning that if the subscript is 0, then the group is not present in the molecule, whereas if the subscript is 1, then the group is present in the molecule; n, n', and n" are, independently, zero or on average at least 1, andat most 14; the sum of n, n', and n" is 0 or on average at least 3, andat most 42; and m, m', and m" are, independently, on average 0-6, andthe sum of m, m', and m" is 0-18.