Polymer injection has proven in many places to be a successful EOR technique. However, selecting the polymer injection as the Enhanced Oil Recovery technique to develop quite heavy oil reservoirs with strong bottom water drive has been always a challenge in the oil industry but at the same time it can unlock the opportunities with such unconventional reservoirs.

This paper describes the key opportunities and challenges associated with implementing Enhanced Oil Recovery process in which polymer is injected into a clastic reservoir with a strong bottom aquifer drive bearing heavy-oil (250-500 cP). The high reservoir permeability (2-5 Darcy) enables stretching the viscosity limit of a standard polymer application.

There are several opportunities associated with this project but the key once are using low salinity make up water for injection, recycle back produced polymer and using Alkaline Surfactant Polymer at later phase on the project. The use of low salinity make up water was identified as the most important opportunity as it has the potential to substantially improve the project economics by reducing the polymer consumption while obtaining the same subsurface results. It also has the additional advantage to potentially improve the field UR by reducing the Sor. A number of risks are associated with this opportunity, the main ones being in situ clay swelling, reservoir souring, and decreased polymer stability if mixing with formation water occurs.

Conversely, this project is quite challenging specially with the limited analogues in the oil industry. The key challenges are the impact of back produced polymer, work around the congested urban planning and most importantly make the subsurface concept work. Finally, this paper discusses the solutions and activities to address and mitigate these key risks.

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