Study on Foam Generation Mechanism and Deflecting Ability in Porous Media

To clarify the behavior of foam generation and migration in the formation and to examine the basis of its application in oil and gas field development, microscopically etched glass models were used to investigate foam generation mechanism and deflecting ability in porous media by means of visualization experiments. The results show that the neck is easily snapped-off during displacement, anterior neck, and straight neck are easily snapped-off during sucking. When the gas-liquid injection is mixed with water saturation, the process of sucking and displacement will appear alternately, resulting in the change of foam generation mode. It is found that the diameter of foam generated by the anterior cervical blockage is slightly smaller than that of the pore throat of the generating bubble. The diameter of foam generated by straight neck snap-off is about twice that of the pore throat of the generating bubble. The diameter of foam generated by neck blockage is roughly equivalent to that of the pore body. The migration and deflecting ability of foam vary greatly in models with different permeability levels. Generally, the limit of the permeability level difference of foam injection in heterogeneous layers is 6:1, and it is difficult for foam injection alone to affect the low permeability area in models with high permeability levels. It is concluded that the results of the above study can provide some guidance for the application of foam in recovery enhancement.