| Polymer flooding is one of the most common chemical EOR techniques used in EOR projects worldwide. However, field applications of polymer flooding are usually limited by the cost of polymer and its considerable loss during the injection. The injectivity and efficiency of polymer flooding are significantly affected by polymer degradation, polymer retention, and high velocity near the wellbore. A function of nanoparticles---encapsulation---can be used to reduce these adverse impacts. Encapsulating polymer in the nanocapsules can isolate polymer from the environment and from impact near the wellbore for a designated releasing time, thereby reducing the impact near the wellbore. To explore the effect of nanocapsules on polymer injection, numerical models for polymer flooding were applied to test the decrease of injection pressure between encapsulated polymer injection and pure polymer injection, under different values of simulation parameters. The viscosity model was then integrated into an in-house grid-based simulator to simulate the transport of capsules and released polymers in the formation. The result indicates that for an engineered releasing time, encapsulating polymer in the nanocapsules can prevent polymer from contacting the environment near the wellbore, thus reducing the injectivity loss occurring near the wellbore and transporting polymers to further areas in the reservoirs. |
