Research of a New Micro-Nano Oil-Displacement System Conformance Control Technology and its Performance Evaluation

Abstract Although polymer flooding technology has been widely applied and achieved remarkable effect of oil increment. Yet the "entry profile inversion" phenomenon occurs inevitably in its later stage. This exposes the shortcomings of its oil displacement mechanism and ultimately affects the oil recovery rate. Therefore, a novel dispersion system has been developed in recent years. Due to its excellent performance and advanced mechanism, it can effectively overcoming the above issues. The dispersion system consists of microgel particles and its carrier fluid. After coming into porous media, it shows the motion feature of "trapping, deformation, migration". In this paper, the preparation method, reservoir adaptability evaluation, and plugging and deformation characteristics of dispersion system is firstly studied. Then, by adopting the microfluidic technology, its oil displacement mechanism is further explored. On this basis, oil displacement evaluation is carried out through the CT technology. Furthermore, the typical field application case is analyzed. Results show that, the dispersion system have good physical and chemical properties performance and transport ability in porous media. Through microfluidic experiments, the temporary plugging and deformation characteristics of microgel particles in the pore throat are clearly displayed. Additionally, due to the partitioning and cooperation between microgels and carrier fluids, the dispersion system causes no damage to the low permeability layer. Furthermore, microgel particles presents the movement 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, dispersion system can achieve the goal of enhance oil recovery. Finally, the dispersion flooding technology has been applied in 15 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.