Crosslinked Polymer Performance And Tune The Drive Mechanism

During the water flooding and polymer flooding, water and polymer solution mainly are injected into high permeability because of the heterogeneity exiting in layer, which will affect the development effectiveness. To modify the layer's heterogeneity, enhance the recovery after water flooding and polymer flooding, turn the high production and stable production into realization, in recent years, many researches have been done on cross-linked polymer gel by many scientists, but just a little on the profile modification and flooding mechanism of cross-linked polymer gel, this is one of the reason that leads to the difference of profile modification and flooding effectiveness. On the base of many laboratory experiments and field construction, using many methods, such as physical modification, orthogonal design, transition pressure test system and so on, this paper has researched composite ion, Al3+ and Cr3+ cross-linked gel and has completed the research of project's priority selection, oil displacement efficiency, flowing and gel-forming characteristics in porous medium, cross-linking time, cross-linking mechanism, evaluation methods and so on. The results show that there are two kinds of structure, intra-molecular cross-linking and molecular to molecular cross-linking, When intra-molecular cross-linking plays the main role in gel, the viscosity will increase greatly, and when molecular to molecular cross-linking plays the main role, the viscosity almost keeps invariable. The results of sealing off core test show that both of resistance factor (FR) and residual resistance factor (FRR) for gel are much bigger than those of polymer solution, and appears its own special flow characteristic, the FRR is bigger than the FR. The result of evaluation test shows that the transition pressure, FR and FRR are the direct and available index to estimate whether polymer molecular has intra-molecular cross-linking or molecular to molecular cross-linking. The results of cross-linked polymer gel's profile modification and flooding mechanism show that at the first period of gel-forming, cross-linking polymer has low viscosity and good flowing characteristic, and can play the part of flooding. But after gel-formed in core, it has good intensity and stability, and can modify the profile effectively. The technique just is united in reason by flooding and profile modification.