Objective Aiming at the poor development effect of water injection in the medium-low permeability reservoir of Weizhou 12-1 oilfield,the under-injection caused by high injection pressure easily due to the injection gel conditioning,and the foam volume and half-life of foam repellent are greatly affected by the high temperature and high salt environment,etc.,we propose to use the synthesized SMG microspheres,which are controllable in size,stable in nature,and have excellent injection ability and temperature and salt resistance,as the deep driving agent,so as to satisfy the further increase of the production in the field.Methods The hydration swelling performance,injection performance,plugging performance and recovery enhancement effect of SMG deep profile control system were analyzed by scanning electron microscope,laser particle size meter and physical simulation experiments.Results SMG has good swelling and plugging performance,with an initial particle size of 0.71 μm,expansion slows down after seven days,and a final particle size swelling multiple of 5.32 μm,the final particle size expansion ratio was about 7 times.When the core permeability was in the range of 69.8 × 10-3-308.0 × 10-3 μm2,the plugging rate was above 90％in all cases.The resistance coefficient and plugging rate of SMG showed a small fluctuation and then gradually decreased with the increase of core permeability.The highest recovery increase in the experimental group was 15.49％.Conclusions The injection of SMG can achieve deep retention,effectively seal the large pore throat of high permeability,improve the reservoir inhomogeneity.It can change the flow direction and pressure distribution of the drive fluid,increase the wave area to improve the oil recovery,and the earlier the timing of SMG injection,the stronger the ability of pressurization and flooding,the better the recovery enhancement effect.
middle and low permeability reservoirSMGinjection parameter optimizationplugging mechanismenhanced oil recovery
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