Mechanism of surfactant improving injection huff and puff effect in tight reservoir
Water injection huff and puff have been successfully applied to many major oil-fields as an economical and effective method for producing tight reservoirs.Surfactants can enhance tight oil recovery,but their mechanism needs further study.The huff and puff pro-cess is divided into imbibition recovery and reverse displacement recovery,and the effect of surfactants on it is described.The results show that the surfactant can reduce the imbibition recovery but reduce the difficulty of oil stripping from the rock surface.In the reverse dis-placement recovery stage,surfactants can effectively improve the displacement recovery effi-ciency and significantly reduce the displacement pressure.Amphoteric surfactants showed the best performance,increasing oil recovery by about 5.00%based on clean water and re-ducing displacement pressure by about 7.00 MPa.The primary mechanism is to reduce the interfacial tension,change the wettability,and reduce the difficulty of oil stripping from the rock surface.Reduce capillary force and resistance of Jamin effect,and reduce displacement pressure.The results provide a theoretical basis for applying surfactants in injection huff and puff in tight reservoirs.
tight oil reservoirwater injection huff and puffsurfactant
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维普
