Optimization And Evaluation Of Nanometer Microspheres Deep Adjustment Technology

Micro-nano microspheres are an excellent deep flooding agent which is easy to produce and operate. The injectivity, blocking and migration capability of micro-nano microspheres are good. Because of the small initial particle size and good dispersion performance, the microspheres will not block reservoir. The microspheres can be injected into formation without special equipment, which will save construction and labor costs.In this paper, the typical S oilfield was selected. By summarizing the geological and development of the oilfield, such as the permeability ratio, mainstream throat diameter, history of development, quality of injection water and salinity, the flooding experiment evaluated the sensitivity of S oilfield and damage degree of injection water. According to the evaluation results, three kinds of microspheres were selected to carry out laboratory evaluation.We got the following understanding:(1) Static experiments analyzed the particle size, shape, temperature-salt resistance, suspension dispersibility, viscosity, acid-alkali resistant and compatibility with other flooding systems. The results showed that the microspheres would expand to final size within 30 days and the expansion ratio increased with the rise of temperature and decreased with the increasing of salinity. Three kinds of microspheres dispersed system was pure and had good temperature-salt resistance and alkali tolerance. Three kinds of micro-nano microspheres had good compatibility with surfactant and polymer system.(2) The core flooding experiment optimized injection parameters, including the injection concentration, injection volume, and evaluated the blocking capability and the capability to enhance oil recovery.The experimental results showed that the profile control system can be used for polymer injection wells.When the parallel cores were displaced by microspheres system, the flooding system improved oil recovery of low permeability core significantly and enhanced oil recovery of two cores by 15.6?22%, and the split ratio of cores were close to 50%.(3) This paper aimed at the problem of contradiction between interlayer and layer of S oilfield and optimized the displacement system, which was important to enhance oil recovery after polymer flooding and provided a new idea for development.