原油中沥青质的稳定性及其影响因素

Stability and Influencing Factors of Asphaltene in Crude Oil

影响原油中沥青质稳定性因素多且复杂,而原油组分组成变化对沥青质稳定性的影响机理尚不明确。在测定10种不同原油油样密度、黏度、元素组成和四组分(饱和烃、芳香烃、胶质和沥青质)含量的基础上,采用场发射扫描电镜、傅立叶变换红外光谱、X射线荧光能谱和Zeta电位评估等方法,研究了10种原油油样的组分组成及其与沥青质之间相互作用特征,明确了蜡、水和无机盐对沥青质稳定性的影响。研究结果表明,原油的密度和黏度与重烃、轻烃含量之比呈正比,当沥青质含量增加时,原油中H含量和H、C物质的量比降低,非烃含量增加,沥青质的稳定性降低。蜡和水会改变原油组分组成,影响沥青质稳定性。原油中无机、有机金属含量分别介于0.0021%~0.0814%和0.0007%~0.0655%。钒和镍等有机金属会破坏沥青质的稳定性,而储层中无机金属则会增强沥青质稳定性。沥青质沉积物表面存在大量带负电荷的无机微粒,导致其水溶液的Zeta电位值为负。当Zeta电位绝对值越大时,沥青质的稳定性更好,说明由无机微粒产生的电荷可以稳定原油中的沥青质,降低沥青质的聚集倾向。研究成果为有效预防沥青质沉积、缓解沉积伤害提供了参考和借鉴。

the factors affecting the asphaltene stability in crude oil are complex,and the mechanism of the change of crude oil composition on the stability of asphaltene is still unclear.On the basis of measuring the density,viscosity,element composition and four components(saturated hydrocarbon,aromatic hydrocarbon,resin and asphaltene)content of 10 different crude oil samples,the composition of 10 crude oil samples and their interaction characteristics with asphaltene were studied by means of field emission scanning electron microscopy,Fourier transform infrared spectroscopy,X-ray fluorescence spectroscopy and Zeta potential evaluation.The influence of wax,water and inorganic salt on the stability of asphaltene.The results showed that the density and viscosity of crude oil were in direct proportion to the content ratio of heavy and light hydrocarbons.When the asphaltene content increased,the H content and molar ratio of H to C in crude oil decreased,while the non hydrocarbon content increased,and the stability of asphaltene decreased.Wax and water would change the composition of crude oil and affect the stability of asphaltene.The contents of inorganic and organic metals in crude oil were 0.0021%—0.0814%and 0.0007%—0.0655%,respectively.Organic metals such as vanadium and nickel would destroy the stability of asphaltene,while inorganic metals in the reservoir would enhance the stability of asphaltene.There were a large number of negatively charged inorganic particles on the surface of asphaltene sediment,resulting in negative Zeta potential of its aqueous solution.When the absolute value of Zeta potential was greater,the stability of asphaltene was better,indicating that the charge generated by inorganic particles could stabilize asphaltene in crude oil and reduce the aggregation tendency of asphaltene.The research results provided a reference for effective prevention of asphaltene deposition and mitigation of deposition damage.