Study On The Control And Mechanism Of Fluidity And Stability Of Crude Oil With High Viscosity

The high viscous crude oil includes not only waxy-paraffinic-crude oils,in which paraffin content is high,but also heavy crude oil which contain much resin and asphaltene.For the waxy-paraffinic-crude oils,the flow proprty become worse as temperatures lowers than the pour point,due to wax crystallization.For the heavy crude oil with high density and high viscosity,the flow property is poor.Therefore,it is very difficult to explor and transport the high viscosity crude oil.Study of the flow improver for the crude oil is necessary for gathering and transportation of these high viscous crude oil,which is significant to practice.Uing flow improvers and aquathermolysis were employed to improve high viscous crude oil flow properity in this paper.First of all,poly-methacrylamide were prepared from polymethyl methacrylate and polyamines as row materials.The effect of flow improvers on the pour point and viscosity of the crude oils was evaluated.The result shows that:(1)This kind of the flow improver has the poor effect on the viscosity reduction,poly-methacrylamide(PAA-1),with 500mg/Kg,shows the highest reduction rate,only 42% at 45?.(2)This kind of poly-methacrylamide has the significant effect on the pour point depression.PAA-3,with 500mg/L,can depress the pour point of the high viscous oil,among which the highest pour point depression is 15.2?;the wax appearance temperature of the oil is reduced by 0.67?.Then,in order to development a clean aquathermolysis system of heavy oil at relatively low temperature,in this paper,a series of organic Co-salt and Fe-salt were prepared as the catalysts for the catalytic aquathermolysis.Under the best case in which the concentration of Co-3 is 0.5%,the reaction temperature is 180? and the reaction time is 24 h,the heavy oil viscosity reduction ratio reaches to 84.5%.Under the same conditions,Fe-3 as catalyst,the concentration is 0.1%,the heavy oil viscosity reduction ratio can reaches to 80.1%.Result of the heavy oil composition analysis shows that the contents of resin and asphaltene decrease and the saturated hydrocarbon and aromatic increase.TG and GC analysis show that the light components increase remarkably after the aquathermolysis.Duing heavy oil exploitation,the the resin and asphaltene are easy to load on the rock and pipeline surface,which will lead to many difficulties for gathering and transportation.The stabilizer for asphaltene injected to the oil is an effective manner to inhibit the deposition of asphaltene.In this paper,the amount of asphaltene before and after tratment was measured to evaluate the inhibition effect on asphalt depositions.The result shows that: coal tar,with 0.5%,shows the high inhibition on asphaltene deposition.Compared to control test,the amount of asphaltene is decreased from 24.47% to 9.42%.Otherwise,cetyl pyridine bromide has a synergistic effect eith coal tar,the asphaltene content in the crude oil was decreased by 1.74%on the basic of coal tar.Dehydration and desalination is very important during the gathering and transportation of crude oil.By a series of experiments on aliphatic alcohols and 21 demulsifiers supplied by three company to demulsify the crude oil from Jinghe Oilfield by a systematic approach.The result shows that n-pentanol and some demulsifiers have better effect on demulsification as used together.The result shows that mixed demulsifiers might significantly improved the dehydration rate,and it can resolve some problems in the using of demulsifiers.