Volume 62, Issue 341, May - August 2026

Sustainable Enhanced Oil Recovery in the Niger Delta Using Polymer Flooding and Alkaline Flooding

Oritom Hezekiah-Braye¹, Godloves T Nonju²

¹Department of Petroleum Engineering, Faculty of Engineering, P.M.B. 5080, Port Harcourt, Nigeria
²Department of Petroleum Engineering, Faculty of Engineering, P.M.B. 5080, Port Harcourt, Nigeria

ABSTRACT

The increasing demand for environmentally sustainable enhanced oil recovery (EOR) technologies has stimulated interest in replacing conventional synthetic chemicals with naturally occurring materials. Natural alkaline and polymeric substances are increasingly recognised because of their biodegradability, local availability, low cost, and reduced environmental impact. The potential of using mangrove wood ash as a natural source of alkaline material and Caladium bicolor starch as a biodegradable polymer to enhance oil recovery from Niger Delta sandstone reservoirs was investigated in this experiment. To evaluate their effectiveness, core flooding experiments were conducted using ten sandstone cores obtained from Niger Delta. In these experiments, the effect of salinity levels on oil recovery by both flooding agents was investigated. Additional rheological analyses were performed to determine the influence of temperature, concentration, wetting behaviour, and shear stress on the flooding agents. The mineralogical composition of the reservoir rocks was also determined using X-ray diffraction (XRD). The results showed that salinity strongly influenced the performance of both flooding agents. The rise in salinity decreased oil production despite a marginal increase in viscosity of the solution. For mangrove wood ash, the maximum oil displacement efficiency was attained at 1000 ppm with a value of 57.8%, while the lowest efficiency value was 51.0% at 5000 ppm. Likewise, for Caladium bicolor starch, the maximum efficiency value was 57.2% and the minimum value was 47.8%. The lowest water cut was also observed at 1000 ppm, recording 32% for Caladium bicolor flooding and 42% for mangrove ash flooding, whereas the highest water cuts occurred at elevated salinity levels. Unlike many previously reported natural EOR materials that are edible agricultural products, the materials investigated in this study are non-edible and readily available as local waste resources. Their use thus eliminates competition for food sources and decreases reliance on foreign-made chemicals. The results have shown that the use of mangrove wood ash and Caladium bicolor starch will greatly increase oil recovery at low salinity and provide environmental alternatives to chemical EOR in the Niger Delta oilfields.

Keywords: Enhanced oil recovery; alkaline flooding; polymer flooding; mangrove wood ash; Caladium bicolor; salinity; rheology

Discovery, 2026, 62, e22d3293

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Published: 12 August 2026