Crude oil demulsification is a key link in the process of oil and gas gathering,transportation and treatment.The effect of demulsification directly affects crude oil production and subsequent sewage treatment.Chemical demulsification is the most commonly used demulsification technology in oil fields,and the performance of the demulsifier directly affects the demulsification effect.Polyether demulsifiers are the most widely studied and used type of demulsifiers in oil fields.Fluorinated surfactants have excellent characteristics of "three highs" and "two phobias".If fluorine atoms can be introduced into the polyether demulsifier,it will help improve the demulsification effect.In view of the difficulty in demulsification and dehydration of crude oil in the LE block,a new type of fluoropolyether demulsifier was developed.The main results are as follows:The density,composition,freezing point,acid value and water content of crude oil in a block of LE were measured and analyzed.It is determined that the crude oil in a block of LE is a high acid value I-2 grade heavy oil,with a water content of about 35.8%,and the crude oil contains a lot of polar substances,which is easy to form a stable emulsion.Common demulsifiers used in oilfields could not meet the demulsification needs of crude oil emulsions in this block.Synthesize phenol amine resin starter with trifluoromethyl phenol and other substances at 110°C.It was polymerized with ethylene oxide(EO)and propylene oxide(PO)to synthesize fluorine-containing polyether demulsifier FB in a negative pressure of-0.09 MPa and an environment of 130°C.6920,9920,15920 and other 5 hydrophilic and 7 lipophilic polyether demulsifiers were synthesized by changing the ratio of EO and PO.Through infrared spectroscopy,proton nuclear magnetic resonance spectroscopy,surface tension and thermogravimetric characterization,it was confirmed that the demulsifier is successfully synthesized and could effectively reduce the surface tension of the solution.The existence of C-F bond could increase its thermogravimetric performance.The crude oil demulsification test in the LE block showed that the demulsification effect of the FB polyether demulsifier was better than the demulsifiers currently used in the oil field,and the lipophilic demulsifier was better than the hydrophilic demulsifier.Among them,the 159 series and the 37 series had the best demulsification and dehydration effects.The FB polyether demulsifier was crosslinked and modified with TDI to obtain the fluorine-containing polyether demulsifier TFB.The cloud point,HLB value,molecular weight and surface tension of the demulsifier before and after modification were compared and analyzed.The modified TFB demulsifier were oil-soluble demulsifier,which can also effectively reduce the surface tension of the solution.The demulsification and dehydration effect of modified TFB polyether demulsifier was explored.It was found that the optimal modifier dosage was 4% of the mass fraction of polyether,the optimal demulsification temperature was 60℃,and the optimal demulsifier dosage was 50mg/L.Under the above conditions,the overall demulsification rate of TFB15937 demulsifier was as high as 95.53%.The demulsification performance was better than that of unmodified FB polyether demulsifier and on-site demulsifier. |