Use of overbased detergent additives to suspend asphaltene compounds

摘要

Oil-soluble overbased salicylate-phenate detergent additives comprising a complex in which the basic material of the detergent is stabilised by both salicylate and phenate surfactants. The mass % of the salicylate, as a percentage of the total surfactant mass, is at least 50, preferably greater than 50, provided that, when said mass % is less than 60, the TBN: mass % surfactant ratio of the detergent is 10 or less.