阴/非离子型表面活性剂稠油冷采降黏体系微观作用机制OA

As an important method for cold production of heavy oil,emulsification viscosity reduction technology can signifi-cantly improve oil fluidity.On the basis of a self-developed anionic-nonionic composite emulsification system,the structural changes of each component in heavy oil before and after viscosity reductio were systematically analyzed by four-component separation,infrared spectroscopy,and scanning electron microscopy.And the microscopic influence mechanism of viscosity reduction system on the interaction between heavy components was deeply explored by atomic force microscopy.It is found that viscosity reducer molecules can effectively weaken the original association between resins and asphaltenes by enhancing hydrogen bonding and π-π stacking.After viscosity reduction,the resins transform from a dense mass into a porous block structure,while the asphaltenes aggregates is loose and accompanied by surface particles detaching.The iscosity reduction system significantly reduces the adhesion between resins and asphaltenes,and the maximum adhesion decreases from 3.11 and 5.49 nN to 0.8 and 0.5 nN,respectively.With the increase of viscosity reducer concentration,electrostatic repulsion appears between asphaltenes,and the steric hindrance is enhanced.The average grafting point spacing increases from 5.43 to 11.14 nm,and the grafted chain length extends from 1.84 to 6.22 nm.These changes effectively weaken the strength of the three-dimensional network structure of asphaltenes,thereby reducing heavy oil viscosity.