Effect Of Representative Chemical Oil Displacement Agents On Properties Of Crude Oil And Products

With the using of chemical agents on oil field to enhance oil recovery,unfavorable effects on the processing are also generated.Investigation of large amounts of domestic and overseas literatures shows that,dehydration of oilfield produced liquid becomes more difficult after using chemical oil displacement agent,and emulsified oil in waste water increases.However,there are still part of the chemical oil displacement agents being left in crude oil after demusification and dehydration.There are few reports on whether this part of chemical oil displacement agents will have influence on crude oil properties,or the degree of the influence.Therefore,this thesis focuses on the discussions of the influence of typical chemical oil displacement agents(surfactants and polymers)on crude oil properties and the critical concentration value when influences are generated.The wastes generated by the use of chemical oil displacement agents are treated with effect method.In this thesis,firstly compares the properties of crude oil and products between chemical flooding well and water flooding well in Bohai oilfield,and obtains the differences between these two samples.Secondly,adds different concentrations chemical oil displacement agents in the same crude oil,and true boiling point distillation is carried out on crude oil,thus getting the primary processed products of crude oil,then,analyzes the influence rule of the addition of chemical oil displacement agents on the properties of crude oil and products.Finally,effectively disposes the waste by using of chemical oil displacement agents.Conclusions are as follows:(1)The component of resin in crude oil decreases with the increasing of polymer,because of adsorption and flocculation of polymer.Besides,the experimental results show that,when the polymer concentration is above 700mg·L-1,the content of resin decreases obviously,which exceeds the error value by about 2%,and when the concentration is less than 700mg·L-1,the change value of resin content is in the error range,therefore,when the concentration of polymer in produced liquid is less than 700mg·L-1,it has no influence on the crude oil properties.(2)With the increasing of oil displacement agents,the content of calcium gradually increases.High valence cationic(Ca2+)in water displace low valence metal iron(Na+)in surfactant,increase the hydrophobic of surfactant.Carboxyl in polymer could form complexes with calcium(Ca2+)in water,hydrophobic characteristic of polymer increases.In conclusion,the content of Ca increases in crude oil,and also in vacuum residuum.(3)The surfactants in crude oil enhance the acid value of gasoline fraction.Because of the light components generated by thermal decomposition and the existence of organic chloride in surfactants affect the acidity of gasoline.(4)Maximum concentration of oil sludge in crude oil that can reach stable dispersion is 0.5%,hence oil sludge could mixed in crude oil to transported to land for offshore oil field.The influence of oil sludge on crude oil and processed products mainly because oil sludge contains solid particles and polymers,the yield of vacuum residue rises.For the influence on asphalt quality,needle penetration increases,asphalt becomes soft,and the extensibility of asphalt becomes better.(5)A set of economical and effective method of treating aging crude oil is obtained: combined heating and chemical treatment for oil recovery from aging crude oil can achieve excellent results.Based on the experimental results on the treatment of aging crude oil,the treatment capacity of aging crude oil reaches to 87.07%.The influence of oil displacement agents on crude oil quality provide technical support for subsequent use of chemical oil displacement agents,and also offer certain references to the direction of improving chemical oil displacement agents.