Preparation and Use of Water Soluble Demulsifier LS938-2 for Heavy Crude Oil

A water soluble combinational demulsifier, LS938-2, is prepared through following steps: reaction of phenol, polyethylenepolyamine, and formaldehyde in toluene to give an aminated phenolic resin; synthesis of a PO/EO/PO polyether with the phenlic resin as initiator; reaction of the polyether with polymethyltriethoxysilane to give a silicone-polyether; and mixing the silicone-polyether with SP169, an aliphatic alcohol initiated EO/PO polyether to obtaine the end product. The preparing process is described in some detail. When used in laboratory to dehydrating the fresh heavy crude oil samples of water cut 24% and 32% from the old oil gathering/pretreating plant in Jingzhou oil production factory, Liaohe, at dosage 60-120 mg/L and at temperatures 70℃ and 80℃, LS938-2 is much more effective than AF8464, a demulsifier being used in the plant, and the oil/water separation proceeds faster to higher extent (average dehydration increment 26.9%) with sharper interfaces and clearer water phase containing less oil substances. In a comparative field trial on LS938-2 and AF8464 of dosage 90 mg/L at 70℃ performed in the plant, the water cut of the crude oil being treated is decreased to 4.5% and 16.2% before electric dehydration and to 0.15% and 0.41% after electric dehydration, respectively. LS938-2 is a very effective demulsifier for the heavy crude oil.