Synthesis And Application Of The New Crude Oil Demulsifiers

There are abundant petroleum reserves and a long exploitation history for North Shaanxi oilfield, various measures applied to increase production make the water-oil interface more intricacy and the emulsion becomes more stable, so more effective demulsifier are needed. Several excellent demulsifiers are synthesized and choosed by conditions of demulsifying and characteristics of produced fluid and they are used to solve the problems of high demulsifier use level, low dehydration ratio, the large oil content and large suspended matter in sewage and thick middle water-oil emultion layer for Northern Shaanxi Oilfield.The diblock, the triblock and the multiblock TP polyethers are synthesised by TP as primer and ethylene oxide and propylene oxide as monomer. The dehydration ratios of TP polyethers for the Zichang crude oil and Nianzhuang crude oil in Northern Shaanxi oil fields are measured by SY/T 5281-2000(Bottle test method). The test results show for Zi Chang crude oil that TP416 diblock polyether demulsifier have the fastest dehydration speed and TP412 have the highest dehydration rate; and TP4168, TP41616, TP83216,TP83224 triblock polyether demulsifiers have the clear water and highest dehydration rate, and TP4163232, TP832328 multiblock polyether demulsifiers have clear water and highest dehydration rate. For Nianzhuang crude oil, TP412, TP416 diblock polyether demulsifiers have the fastest dehydration speed and highest dehydration rate; TP41632,TP8324 triblock polyether demulsifiers have clear water and highest dehydration rate;and TP416324, TP832324 multiblock polyether demulsifiers have the fastest dehydration speed and highest dehydration rate. TP4168 has the most widely adaptability for different crude oils.The 1-chloro-Octadecane, bromododecane and hydrophilic radical(synthesised in laboratory) are used to synthetic reaction, obtained the CT and BT series reversedemulsifiers. The structure of CT and BT series reverse demulsifiers was indicated by IR.Critical micell concentrations of the CT and BT are obtained by conductivity method, the product’s surface tensions are determined by maximum bubble pressure method, the results show that reverse demulsifiers are better surfactants. The dehydration ratio of the reverse demulsifier combination with the polyether TR8328 is been studied, salt content in purified oil and oil content in sewage were measured at same time. The test results show that the combinational demulsifier of TR8328 and CT04 had good dehydration rate and strong applicability. For Zichang crude oil, the dehydration ratio of the combinational demulsifiers is 97.7% and salt content in purified oil is 0.048mg/L, oil content in sewage is 26.2mg/L, separated water is clear, interface between water and oil is homogeneous when TR8328 : CT04 is 160mg/L : 40mg/L; for Nianzhuang crude oil,the dehydration ratio of the combinational demulsifiers is 100.0% and salt content in purified oil is 0.039mg/L, oil content in sewage is 6.9mg/L, separated water is clear,interface between water and oil is homogeneous when TR8328 : CT04 is 80mg/L :20mg/L. The dehydration ratio of the combinational demulsifiers is higher than only polyether, the dehydration ratio and speed are enlarged significantly by combination.