Schematic illustration for the enhanced oil recovery mechanism.

<p>(a) oil distribution in the initial stage of reservoir development; (b) a high permeability zone formed after long-term water flooding; (c) injection of DPG particles for profile control; (d) DPG particles deform and pass through pores; (c) water flooding after the treatment.</p

Visual simulation results in etched glass model.

<p>(a) model; (b) saturating water; (c: saturating oil; (d) water flooding until water cut is up to 98%; (e) retention in larger pore space; (f) directly plugging the small pore throat; (g) segregated flow of oil and water pathway; (h) adsorption on the surface; (o) water flooding until water cut is up to 98% again.</p

DPG particle distribution in etched glass model at different magnifications.

<p>(a)∼(d): 40× magnification; (e)∼(f): 100× magnification.</p

Disproportionate permeability reduction of DPG particles.

<p>Disproportionate permeability reduction of DPG particles.</p

The profile improvement capacity of DPG particles.

<p>The profile improvement capacity of DPG particles.</p

Visual simulation results in a flat panel sand model.

<p>(a) model; (b) saturating water; (c) saturating oil; (d) water flooding until water cut is up to 98%; (e) injection of DPG particles for 6 min; (f) injection of DPG particles for 9 min; (g) injection of DPG particles for 15 min; (h) injection of DPG particles for 20 min; (o) water flooding until water cut is up to 98% again.</p

The morphology and size distribution of typical DPG particles.

<p>(A) The TEM morphology of nano-size DPG particles; (a) Nano-size DPG particles with an average size of approximately 108 nm; (B) The TEM morphology of micron-size DPG particles; (b) Nano-size DPG particles with an average size of approximately 5.6 µm; (C) mm-Size DPG particles with an average size of approximately 3.2 mm.</p

The single tube experimental model.

<p>The single tube experimental model.</p

The visual simulation experimental flow chart.

<p>The visual simulation experimental flow chart.</p

The multi-point pressure physical model.

<p>The multi-point pressure physical model.</p