Abstract: The water swelling materials with molecule interpenetrating networks structure have many excellent characteristics，such as controllable swelling speed and super intension after swelling.The injection performance and the migration characteristics after swelling of water absorbing particles indepth fluid diversion agent are studied by physical simulation experiment of sand packed model and telescoping pipeline model.The experiment results indicate that the particles before swelling can be injected successfully when the diameter of particles is less than that of pore throat.After particles swell，they can successfully pass the pore throats whose diameter is more than that of particles by extending deformation.The deformation can be immediately restored after passing.The permeability of sand packed model decreases during injection process of particles.The permeability is less after particles swell.The swelling particles can pass through pore throat when the displacement pressure is enough.

Key words: water absorbing particles, in depth fluid diversion agent, injection performance, displacement pressure, migration