Abstract: This is the fourth paper studying the viscoelaticity of retained polymer molecules in porous media, (1) (2) (3) A comparison of molecular flexibility is made between HPAM and Xathan Gum. It has been shown theoretically that the viscoelastic recovery of the flexible retained molecules causes the effective flowing area of throat to decrease exponentially, and thus causes the flow rate to decrease in the same manner. Based on this, a new method has been developed for measuring the relaxation time of retained polymer molecules in porous media.The effect of core permeability and soulution salinity on viscoelastic flow has also been studied.

Key words: Polymer, Viscoelastic property, Porous media, Measurement