Abstract: The weak gels based on partial hydrolyzed polyacrylamide(HPAM) aqueous solutions gelated by organic crosslinkers were investigated rheologically with application background of tertiary oil recovery. The linear and non-linear rheological properties in gelation processes of weak gels with different crosslinkers reveal two kinds of textures near the gel point, one is a fractal network, and the other is a heterogeneous network with a characteristic dimension. The optical microscopic approved the rheological arguments. High shearing and the stretch flow in converging outlet measurements indicat that contrary to the static colloidal gels, the strong flows can reinforce the integrities of network structures and enhance the rheological properties. The potential in the EOR applications are also discussed.

Key words: Hyalrolyzed polyarylamide, Weak gel, Rheology, Gel texture, Elongational viscosity