Experimental Study on Improving Recovery Rate of Tight Sandstone Reservoirs with Surfactants
A self-made surfactant FDP suitable for tight sandstone reservoir recovery was prepared.The reservoir characteristics of the target reservoir were analyzed using X-ray diffraction,scanning electron microscopy,and interfacial tension meters.The influence of FDP on rock interfacial tension and wettability was tested,and the static and dynamic adsorption characteristics of surfactant FDP and SDS solution during oil recovery were evaluated using a rock core displacement experimental device,a comparative analysis was conducted on its effectiveness in terms of infiltration and extraction yield.The results showed that the surfactant FDP could effectively achieve oil displacement effect in porous media by changing rock wettability,reducing oil-water interfacial tension,and emulsifying effect.The main pore type of the target block oil reservoir is feldspar dissolution pores,with poor connectivity and overall weak hydrophilicity.The 0.02%FDP system had an oil-water interfacial tension of only 2.33 mN·m-1 and a three-phase contact angle of less than 30°.Its recovery rate in static and dynamic infiltration was significantly higher than that of the SDS system,which could effectively improve the recovery rate of tight sandstone reservoirs.
Dense sandstoneSurfactantsInterface tensionRecovery ratio
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