First Nanoparticle-Based EOR Project in Japan : Field Pilot Test

Abstract Nanoparticle-based enhanced oil recovery (Nano-EOR) is an improved waterflooding assisted by nanoparticles dispersed in injection water (nanofluid). Although Nano-EOR has been revealed to become a promising technique from many laboratory experiments, field applications are still limited. This paper discusses the first Nano-EOR field pilot tests for the Sarukawa oil field in Japan. The field pilot tests were divided into two stages: short-term injection test and long-term inter-well test. The short-term injection test was performed mainly to investigate the effects of nanofluid on the well injectivity. Nanofluid was injected into an existing water injection line by an air-driven liquid pump at a concentration of 0.5 wt. % which was optimized in the series of our study. The result of the short-term injection test showed that the nanoparticles used in this study can be injected into the target formation without any damage when the concentration is properly controlled. For the long-term inter-well test, 0.5 wt. % nanofluid was injected into the injection well for two months to validate the increase in oil production. The production behavior was monitored frequently and compared to the reference decline curve. Inductively coupled plasma optical emission spectroscopy (ICP-OES) analysis of the production fluid was also performed to detect the breakthrough of the injected nanoparticles. Although nanoparticles were not detected in the producer well, the oil production rate showed a positive deviation from the estimated baseline decline curve, suggesting an increase in oil production due to the nanoparticles injected from the injector. This paper has made a comprehensive discussion and summary of the challenges based on the current status of the long-term inter-well test. This study established a simple pilot scheme for Nano-EOR and this will contribute to the upcoming Nano-EOR projects.