The Research Of Foaming Characteristic And Mechanical Defoaming Methods On CO₂ Flooding Crude Oil

After gas-channeling happening in CO₂ flooding,the content of CO₂ in the produced fluid will increase a lot.There may be some problems in the operation of separators such like insufficient gas-liquid separation and oil-overs.In order to solve crude oil foaming problems and improve the efficiency of separators,it’s necessary to study the foaming characteristics of CO₂flooding crude oil and the collapse characteristics of crude oil foam under the function of mechanical components.A gas-liquid separation experimental device was designed to simulate the on-site crude oil foam,and two foam evaluation methods,namely the pressure reduction method and the air flow method,were developed.The effects of temperature,pressure drop,and crude oil composition on the foam characteristics of CO₂ flooding crude oil were studied.It’s found that the stability of crude oil foam is mainly affected by temperature,and the higher the temperature,the lower the foam stability,the greater the pressure drop,the stronger the foaming capacity.Adsorption of polar components at the gas-liquid interface enhances the foaming and stability of the crude oil.The higher the viscosity of the water-containing crude oil,the stronger the foam stability,and the water droplets adsorbed on the surface of the foam film can affect the foam stability.Simulated separation experiment and defoaming net experiment were carried out.It’s found that increasing the retention time can reduce the foam in the separator.When the retention time is too short,there is a risk of oil-overs.The defoaming net has a better effect for foam containing less liquid.The defoaming effect of defoaming net increases with the material strength,the number of layers,the mesh number and the wire diameter.The defoaming effect of the separator inlet is related to the feed rate.