# Polymer Flooding in Space-Constrained Reservoirs: Technical and Economic Assessment of Liquid vs. Powder Polymers

## TL;DR

This study compares liquid and powder polymers for oil recovery in tight Austrian reservoirs, finding powder polymers more effective and cost-efficient in the long term.

## Contribution

The study introduces a comparative technical and economic assessment of liquid and powder polymers in space-constrained, low-permeability reservoirs.

## Key findings

- Powder polymers showed better injectivity and mechanical stability in low-permeability reservoirs compared to liquid polymers.
- Economic analysis revealed powder polymers are more cost-effective over a 10-year period despite higher initial costs for liquid polymers.
- Incremental oil recovery of up to 8% was observed with powder polymers at higher viscosity slugs.

## Abstract

This study evaluates the technical and economic feasibility of liquid polymer emulsions as substitutes for powder polymers in polymer flooding applications, particularly in space-constrained, low-permeability reservoirs in Austria. Rheological tests determined that target viscosities of 20 mPa·s at 20 °C and a shear rate of 7.94 s−1 were achieved using concentrations of 1200 ppm for liquid polymer 1 (LP1), 2250 ppm for liquid polymer 2 (LP2), and 1200–1400 ppm for powder polymers. Injectivity tests revealed that liquid polymers encountered challenges in 60 mD and 300 mD core plugs, with pressure stabilization not achieved at injection rates of 1–2.5 ft/day. Powder polymers demonstrated stable injectivity, with powder polymer 1 (PP1) showing an optimal performance at 10 ft/day and a low residual resistance factor (RRF). Two-phase core floods using PP1 and powder polymer 2 (PP2) at 1 ft/day yielded incremental oil recovery factors of approximately 5%, with a maximum of 8% observed for higher viscosity slugs. Economic analysis indicated that over a 3-year horizon, liquid polymers are 30% cheaper than powder polymer Option 1 but 100% more expensive than Option 2. Over a 10-year horizon, liquid polymers are 50% more expensive than both powder polymer options. Although liquid polymers offer logistical advantages, they are unsuitable for low-permeability reservoirs. Powdered polymers, particularly PP1, are recommended for pilot implementation due to superior injectivity, mechanical stability, and recovery performance.