Preparation method of demulsifier for high-asphaltene-content crude oil

The invention provides a preparation method of a demulsifier for high-asphaltene-content crude oil. The preparation method specifically comprises the following steps: (1) adding phenol and toluene into a reaction kettle in a proportion of 1 to (1.3-1.6), and adding a DMC catalyst; (2) adding an initiator, a demulsifier intermediate I and a demulsifier intermediate II which are obtained in the step (1) into a reaction kettle through extraction, and adding a 50% sodium hydroxide methanol solution through extraction; (3) adding dodecylbenzene sulfonic acid into the reaction kettle, and dropwise adding triethanolamine from a dropwise-adding tank; and (4) adding an intermediate III and an intermediate IV into the reaction kettle in a weight ratio of 17 to (2-3), heating to 50 DEG C, and discharging, so as to obtain the demulsifier for the high-asphaltene-content crude oil. The preparation method has the advantages that aiming at the problem of low dehydration speed in an initial demulsification stage of the high-asphaltene-content crude oil, a high-polymer demulsifier containing a large number of branched chains is synthesized, so that the dehydration speed in the initial demulsification stage can be substantially increased; meanwhile, by supplementing an intermediate B, the final dehydration rate reaches above 90%; and the preparation method has the characteristics of high pertinence, high dehydration speed and excellent effect.