The Rheological Behavior Investigation And Penetration Performance Of Air Foam In Porous Media

Foam flooding attracts more and more people’ attention by its unique penetrationperformance, especially air foam flooding. The air foam has both advantages of airflooding and foam flooding, not only to improve the efficiency of sweep, but also toimprove the efficiency of oil displacement. At the same time, it overcome theshortcomings of purging air channeling, and solve the situation that the supply of gasis lack and the cost is too high.Air foam mainly composed of foam liquid and air, so the rheological behaviorand penetration performance of air foam in porous media are different with liquid,such as the water, the polymer solution and the colloidal liquid polymer, and alsodifferent with gas.The experimental showed, the characteristics of the three kinds of foams (ZY,KWY and HY-4) are increasing with the increasing of the foam dosage. Formationwater has an important influence to the characteristics of foams. When the salinity isincreasing from0to166077mg/L, some characteristics of foam are decreasing,include foam volume, foam half-life and foam composite index. When using differentgas to foaming, the nitrogen better than carbon dioxide, and the air is best.The effective content of ZY foams is30%, the best dosage is0.5%. ZY foams canwell to adapt the change of temperature, especially when temperature between with70℃and90℃, the effect of foam is well. When the pressure is increasing from0.1MPa to15MPa, both foam volume and stability are increasing.The mass fraction of ZY foams between0.75and0.96. The foams belong tonon-Newtonian fluid, shear rate has an important influence to the viscosity of foams.The foam viscosity penetrating in rock pore media decreases by the increase of shearrate.The air foam rheological behavior is of shear thinning accord with power-lawindex equation. The viscosity calculations follow as=409.60.70. Andconsistency coefficient K is409.6, the power law exponent n is0.30. The coreflooding experimental showed, the seepage rate have an important influence to the characteristics of ZY foams in porous media. The smallest line speed to make the ZYfoam to foaming in porous media is0.3m/d; when the line speed from0.3m/d to1m/d,the resistance coefficient (sand filling the whole tube) of foam system increasing from14to64.The average resistance coefficient of about70, the seepage rate has lessaffected to the foam plugging capacity. When the permeability is increasing from25610-3m2to85210-3m2, the plugging capacity is gradually increasing. Andhigher pressure, the plugging capacity is bigger.