The Latest Research Progress of Micro-Nano Dispersion System Conformance Control Technology–From Theoretical Research in Laboratory to Field Trail

Although polymer flooding technology has been widely applied and achieved remarkable effect of increasing oil. Yet the "entry profile inversion" phenomenon occurs inevitably in its later stage, which seriously affects the development effect. The dispersion system is a novel flooding system developed in recent years. Due to its excellent performance and advanced mechanism, it can slow down the process of profile inversion, and achieve the goal of deep fluid diversion and expanding swept volume. The dispersion system consists of dispersion particles and its carrier fluid. After coming into porous media, it shows the properties of "plugging large pore and leave the small one open" and the motion feature of "trapping, deformation, migration". In this paper, the reservoir adaptability evaluation, plugging and deformation characteristics of dispersion system in pore throat is explored. On this basis, by adopting the microfluidic technology and CT tomography technology, the research on its oil displacement mechanism is further carried out. Furthermore, the typical field application case is analyzed. Results show that, particles have good performance and transport ability in porous media. The reservoir adaptability evaluation results can provide basis for field application scheme design. Through microfluidic experiments, the temporary plugging and deformation characteristics of particles in the pore throat are explored. Also, the particle phase separation occurs during the injection process of dispersion system into the core, which makes the particles enter and plug the large pore in the high permeability layer. Therefore, their carrier fluid displace oil in the small pore, which works in cooperation and causes no porous media and the distribution law of remaining oil during displacement process are analyzed. It shows that, particles presents the motion feature of "migration, trapping, and deformation" in the porous media, which can realize deep fluid diversion and expand swept volume. 3D macro physical simulation experiment shows that, particles can achieve the goal of enhance oil recovery. Finally, the dispersion flooding technology has been applied in different oilfields, which all obtained great success. Through interdisciplinary innovative research methods, the oil displacement mechanism and field application of dispersion system is researched, which proves its progressiveness and superiority. The research results provide theoretical basis and technical support for the enhancing oil recovery significantly.