稠油活化剂降黏机理及驱油效果研究

稠油降黏冷采是海上油田开发的主要方式,为深入认识稠油活化剂的降黏机理及其在原油黏度为150～1 000 mPa·s的稠油油藏中的应用效果,通过室内物理模拟实验和耗散粒子动力学模拟技术,研究了稠油活化剂对稠油的降黏机理及驱油效果。结果表明,稠油活化剂可提高水相黏度、降低油水界面张力,能有效降低常规可流动稠油的黏度。分子尺度上的研究结果显示,稠油活化剂分子对沥青质聚集体有明显的阻聚-分散效果,其活性基团能增大沥青质芳香盘的层间距和链间距,减小沥青质聚集体堆积高度和堆积层数,削弱沥青质间的相互作用,破坏稠油重质组分聚集结构,分散稠油,从而增强原油流动能力。稠油活化剂的多种机理协同作用使其在室内岩心驱替实验和矿场应用中,均可起到良好的降水增油效果。该研究从分子层面明确了活化剂降低稠油黏度机理,为稠油活化剂现场应用提供理论指导。

Study on Viscosity Reduction Mechanism and Oil Displacement Effect of Heavy Oil Activator

Viscosity reduction and cold production of heavy oil is the main method for offshore oilfield development. In order to deeply understand the viscosity reduction mechanism and application effect of heavy oil activator in heavy oil reservoirs with crude oil viscosity ranging from 150 mPa·s to 1 000 mPa·s, by means of indoor physical simulation experiment and dissipative particle dynamics simulation technology, the viscosity reduction mechanism and displacement effect of the activator on heavy oil was studied. The results show that the heavy oil activator can increase the viscosity of the water phase, reduce the oil-water interfacial tension, and can effectively reduce the viscosity of the conventional flowable heavy oil. The research results on the molecular scale show that the molecule of heavy oil activator has a significant inhibitory-dispersing effect on asphaltene aggregates. The active groups in the activator molecule can increase the interlayer spacing and chain spacing of the aromatic hydrocarbon in asphaltene, reduce the asphaltene aggregation height and layers, weaken the interaction among asphaltenes, destroy the aggregation structure of the heavy components in heavy oil, and disperse the heavy oil, thereby enhancing the fluidity of crude oil. Whether in indoor core displacement experiments or in field applications, the synergistic effects of multiple mechanisms of heavy oil activators can achieve good water decrease and oil enhancement effects. From the molecular level, the study clarified the viscosity reduction mechanism of heavy oil activator, which can provide a theoretical guidance for the field application of heavy oil activator.