水驱原油组分蚀变的地球化学响应及控制因素

注水开发是常用的提高采收率技术，水驱油过程中注入水、原油、储层矿物的长期接触，以及油-水-岩相互作用引起的原油组分蚀变，成为油藏地球化学研究的热点。结合实验室物理模拟和实例监测研究，总结了水驱原油物性、族组成、饱和烃生物标志物、芳烃生物标志物、全油和馏分碳同位素的变化特征。从注水开发过程中水洗作用、生物降解作用、地质色层作用、储层特征差异及润湿性变化等控制因素的角度，评述了各自对原油组分的影响机制和蚀变趋势。考虑到水驱过程中蚀变因素与原油流动间的复杂联系，提出要充分发挥全二维气相色谱-飞行时间质谱精细表征原油组分，核磁共振技术测定原位储层润湿性，物理模拟实验与生产动态监测科学结合确定蚀变综合效应，重点解决浅层油藏中生物降解与水洗作用的叠加效应、水驱油过程中储层润湿性反转节点、水驱油的微观过程和原油组分的动态变化等关键问题。

Geochemical Alteration of Waterflooded Oils and the Controlling Factors

Waterflooding is one of the most commonly used methods for enhancing oil recovery. Due to the long-term contact of injected water, crude oil and reservoir rock during the water flooding oil process, the interaction of oil-water-rock may cause oil compositional modification, which becomes the research focus of reservoir geochemistry. Combined with the results of the laboratory modeling and case study, the dynamic variation of oil property, bulk composition, saturate biomarkers, aromatic biomarkers, carbon isotopes of whole oil and oil fractions were summarized. The affecting mechanism and altering yields of water washing, biodegradation, geo-chromatography, different reservoir characteristics and wettability on the oil compositions during the process of water flooding were comprehensively reviewed. Allowing for the complex relation between those controlling factors and the waterflooded oil flow, three critical issues, such as distinguishing the superimposed effects of biodegradation and water washing in shallow waterflooded oil reservoir, defining the key points for the inversion of reservoir rock wettability, depicting the microscopic process of water flooding and changing regularity of oil composition were proposed to be preferentially resolved, coupled with three techniques including the characterization of oil composition by comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometer, the quantitation of the in-situ reservoir wettability by nuclear magnetic resonance, the evaluation of the altering effect by the association of physical simulation experiment and dynamic production surveillance.