Study On The Relationships Between The HLB Values And Emulsification Behaviors Of Heavy Oils

Heavy oil reserves are abundant in China.Exploitation and utilization of these resources has a great importance in solving the shortage of petroleum resources.Heavy oils with high viscosity and poor fluidity cause the exploitation difficulties,which can be mainly solved via viscosity reduction technology.At present,emulsification viscosity reduction technology is considered to be one of the most promising technologies because of simple procedure and high efficiency,always used in reservoir exploitation,viscosity reduction in well pipe and pipeline transportation.Emulsified viscosity reduction reagents are used in the emulsification viscosity reduction,However,although promising effect raises in the oil procedure,the application range of the reagents is relatively narrow,owing to the complexity and diversity of heave oil.The suitability of oil with reagents need to be explored.One of the important factor to define the hydrophilicity and hydrophobicity of the emulsifiers is the Hydrophile-Lipophile Balance value(HLB),which can be used to display the hydrophilicity and hydrophobicity of heave oil and its interaction with emulsifiers.Analysing the relevancy of hydrophilicity and hydrophobicity and structure of asphaltene,the effect of emulsifiers HLB and heave oil HLB on the emulsifying system can be disclosed via characterizing the relation between compozision and constitution of crude oil and its HLB,and the relation between emulsifiers HLB and heave oil HLB and adaptation and stability of emulsion.This has importance for the exploitation,transportation and following processing,and the further study on the mechanism of heave oil emulsion.The Ming Hua and the LD heavy oils are used as raw materials.The HLB values of the two kinds of heavy oil were measured by conventional emulsification method.According to the measurement mechanism of the HLB values of heavy oil,the influence of heavy oil components on the HLB values of heavy oil was explored from the perspective of interfacial film.The results show that asphaltene is the main component that affects the HLB value of heavy oil,and its composition and structure play a decisive role in the HLB value of heavy oil.Heavy oil with high HLB value has high asphaltene content and high viscosity,and asphaltene contains more aromatic structures,exhibiting higher degree of condensation and more polar functional groups.The formulation of emulsifying viscosity reducing system for Minghua heavy oil,according to the HLB value of heavy oil,was screened out.The viscosification rate reached 99.36%with the dosage of 0.8%,and the water diversion rate in 1h was higher than80%,which met the industry standard.The interfacial tension,Zeta potential and droplet size of the emulsion were measured to explore the action mechanism of mixed emulsifiers with different HLB values on the emulsion.It shows that when the HLB of the mixed emulsifier(HLB=9.65)is close to the HLB of the heavy oil(HLB=8.58),the minimum droplet size,the highest Zeta potential and the lowest interfacial tension are observed in the emulsion.In other words,when the HLB of the mixed emulsifier is matched with the HLB of the heavy oil,it is conducive to increase the electrical repulsion between the droplets,in which the droplet size is minimum,the active agent molecules are compactly arranged on the oil-water interface,and the system shows best stability.Regarding asphaltene,the main component that affects the HLB value of heavy oil,as macromolecular surfactant,its HLBasp were calculated by NMR method,which disclosing the quantitative relationship between HLBasp and its structure and properties.The HLBasp are related to the structure and properties of asphaltenes.The HLBasp varies monotonically with the aromatic-carbon ratio of asphaltenes,the hydrogen substitution ratio around the aromatic ring system and the content of N and O.The HLBasp increases with the increase of f _A and N and O content,and decreases with the increase ofσ.The acquisition of its HLB value is of great significance to further study the emulsification properties of heavy oil.