Theoretical Study on the Micro-Flow Mechanism of Polymer Flooding in a Double Heterogeneous Oil Layer

Critical issues in the development of oil fields include differences layer properties as well serious interlayer conflicts and disturbances that can lead to formation a preferential flow pathway. In order understand disturbance mechanism between heterogeneous layers, mathematical models polymer, two-phase micro-flow porous media are established based on Navier-Stokes equation. The phase-field method is used track interface during displacement process. Then, influences wettability, injection modes, permeability contrasts front length coefficient efficiency studied. results showed when rock surface water-wet (oil-wet), polymer displaced low (high) first, breakthrough obvious early stages displacement. After broke through, (oil-wet) rocks began displace high (low) layer, pathway formed, which slowed subsequent flooding. When oil-wet, perforation degree inlet had greater effect micro-oil efficiency. full commingling production model 26.21% 37.75% higher than separate-layer production, partial production-injection models, respectively. larger contrast, more breakthrough. This study reveals influence different wettability characteristics, micro-heterogeneous provides an important theoretical basis for formulation enhanced recovery schemes layers.