Feasibility Study On Microspheres / Surfactant Flooding In High Temperature And High Salinity Reservoirs In

Currently, as the strong plane and interlayer heterogeneity, ultra depth(>3000m), high temperature(85℃), high salinity(>20x10mg/L) and extremely high Calcium and magnesium ions content existed in Xidaliya oilfield, it led a fast watercut rising, a low recovery during reservoirs development, andthere were not the corresponding matching technology for improving flooding development and enhancing oil recovery when reservoir came into high water cut period. To improve the effect of reservoir development and enhance oil recovery, the paper carried out the feasibility research of microsphere/surfactant flooding technology, completed the following major tasks and obtain the corresponding results:(1)Screened the A37surfactant oil displacement system suiting to Xidaliya high temperature and pressure reservoir through the experiments of interfacial tension, hot salt stability evaluation, emulsion and absorb. This surfactant oil displacement system had the advantages of reducing interfacial tension strongly, good hot salt stability, low absorb content, and a good emulsion ability with oil simultaneously.When the surfacrtant concentration was0.2%, the oil-water interfacial tension still could reduce to10-3mN/m extra-low interfacial tension by aging180d under the condition of reservoir temperature(100℃) and salinity(22.45×104mg/L).(2)Carried out the study of microsphere and surfactant interplay, and got themicrosphere Z10which had a good expansibility and stability under high temperature and salinity condition. The microsphere and surfactant system had a good synergy, it could keep the interfacial tension extra-low.(3)The results of surfactant displacement experiments in homogeneous core showed, the surfactant displacement could enhance oil recovery by10.08%～16.28%after the economic limit of water flooding when core permeability was during69.8～192.5mD. The physical simulation of microsphere matching with various permeability core showed, Z10was better suitable for high permeability layer (>300mD), and microsphere displacement could enhance oil recovery6.67%～10.14%respectively.(4)The microsphere/surfactant experiments pointed out, microsphere which grain size were5～10μm had a relatively better displacement effect under the permeability range of242-1563mD, and the system flooding stage could enhance oil recovery10.48%～24.05%after economic limit of water flooding.In this paper, the microsphere/surfactant compound displacement system has a good adaptability at this reservoir condition, the research results provide the technical reserves for the work of enhancing oil recovery of Xidaliya oilfieldeld, and has a certain guiding significance and practical application value for similar high temperature and salinity reservoir.