Flow mechanism of aqueous dispersion system of nano/ micron-sized polymer particles in low permeability reservoir

Key words:  low permeability reservoir  nano/micron-sized polymer particles  microporous membrane filtration method  flow mechanism

Abstract:

The distribution characteristics of nano/micron-sized polymer particles size before and after filtering with microporous membranes were studied by the laser particle size analyzer, which were used to simulate the throat of low permeability reservoir. The influences of hydration time, injection pressure, microporous membrane size, polymer particle size and concentration on distribution characteristics were also analyzed. The results show that there exists an optimal hydration time range with more than 240 h on the condition of fixing other parameters, during which the gradually increasing elastic deformation of polymer particles makes larger polymer particles to flow the 1.2 μm throat. It is also found that increasing injection pressure contributes to larger polymer particles flowing through the 1.2 μm throat. However increasing polymer particles concentration can enhance the plugging effect of polymer particles in the 1.2 μm throat. The different distributions of polymer particles size are appropriate to certain throat sizes. The range with more than or equal 3.0 of δ, which is the ratio of polymer particle size to throat diameter, is the region of polymer particles directly plugging, the range with more than or equal 1.0 and less than 3.0 of δ is the region of elastic flow, and the range with less than 1.0 of δ is the region of bridging plugging.