Paper Number
EF5 

Session
Emulsions, Foams, and Interfacial Rheology

Title
Effects of elastic flow instabilities on oil displacement in regular and irregular porous networks

Presentation Date and Time
October 9, 2017 (Monday) 11:30

Track / Room
Track 1 / Crystal A

Authors (Click on name to view author profile)

1. Sinha, Indranil (Texas Tech, Mechanical Engineering)
2. Narayan, Shweta (University of Minnesota, Mechanical Engineering)
3. Shi, Xueda (Texas Tech, Mechanical Engineering)
4. Dutcher, Cari (University of Minnesota, Mechanical Engineering)
5. Christopher, Gordon F. (Texas Tech, Mechanical Engineering)

Author and Affiliation Lines (in printed abstract book)
Indranil Sinha¹, Shweta Narayan², Xueda Shi¹, Cari Dutcher², and Gordon F. Christopher^1
1Mechanical Engineering, Texas Tech, Lubbock, TX 79409; ²Mechanical Engineering, University of Minnesota, Minneapolis, MN 55455

Speaker / Presenter 
Sinha, Indranil

Text of Abstract
Polymer flooding is an enhanced oil recovery technique used after both primary and secondary recovery have been exhausted and can often produce 30-60% of a wells output. Although, initially it was believed increased viscosity was the mechanism of enhancement, recent studies of porous elastic flows have indicated that displacement is improved by the changes to flow patterns caused by instabilities.

In this work, we demonstrate oil displacement by polymer flooding is improved in comparison to Newtonian fluid due to flow patterns caused by elastic instabilities at critical Mach numbers, and not due to increased excess pressure drops. This primarily appears due to the ability of the elastic instabilities to overcome capillary pressure in locally trapped oil bridges between solid surfaces and to better penetrate trapped regions of oil through normal velocities. Furthermore, we find that the nature of the porous network has a pronounced effect on the efficacy of this mechanism. Using square packed cylinder grids, hexagonally packed cylinder grids, and mock sandstone geometries, it is observed that polymer flooding is benefited by non-regular porous networks, which allow the normal velocities created by instabilities to better displace flow. Finally, we observe the effect of fractures in the geometries on the ability of polymer flooding to displace oil. Above critical Mach numbers, polymer flooding is able to better penetrate denser networks than Newtonian fluids due to the normal flow velocities that develop.