Emulsifier And Elements Effecting Study In Oil Displacement Process Of Surfactant-Polymer Flooding

The new emulsification performance method for emulsifier was established, the emulsification mechanism of oil displacement agent and its effect on the recovery of SP binary combination flooding were discussed, besides, the influencing factors on SP Flooding were also studied and sorted.In this subject, based on the national standards and ministerial standards, with self-made emulsifying machine, the emulsion mainly used in oilfield was prepared and evaluated. Emulsifying machine was made with meshes to better simulate the actual formation reservoir conditions. The measurement conditions of emulsifying stability were determined, that is, when the oil water ratio is 2:8, the emulsifying machine speed is 2m/min, and emulsifying time is 1h, the formed emulsion is the most stable. Spectrophotometry method was applied for emulsifying ability test, and emulsifier concentration is 0.05%. The evaluation has combined both emulsfying stability and emulsifying ability, the concept of emulsion composite index was also proposed to evaluated the emusifying ability in more angles and aspects.Polymer/surfactant (SP) binary flooding is an EOR technology following polymer flooding and ASP flooding, and its main mechanism is, by adding polymer and surfactant in injection water, the mobility control ability of polymer and a significant reduction of oil-water interfacial tension of surfactant are utilized, the sweep efficiency as well as the displacement efficiency are both improved, and ultimately the oil recovery is also improved. On the basis of a comprehensive research in the mechanism of SP flooding, the mechnism of SP system on residual oil was investigated from a macroscopic perspective systematically. Through oil flooding experiment with natural Berea cores, oil displacement process of surfactant flooding was recorded, and the effect of different viscosity grades, interfacial tensions, emulsification performance on SP Flooding recovery were discussed and sorted.Macroscopic experimental results showed that the system with high elasticity and low interfacial tension can get the highest sweep efficiency and displacement efficiency; viscoelasticity has the greatest impact on enhancing oil recovery, and interfacial tension and emulsification also play significant roles in the recovery ratio improvement. It was also found in the study that when the interfacial tension of oil displacement agent was at the magnitude of 10-1 level, for the water-wet core, the better the emusification performance was, the higher the dispalcement efficiency was. Emulsification took on a prominent effect in this situation.