Two third of the reservoir oil left by the traditional primary and secondary oil production methods can be recovered by techniques employed at the third phase, commonly known as Enhanced Oil Recovery (EOR). Appreciable decline in the new reservoirs discovery and increase in the petroleum demands has forced oil companies to develop various EOR methods. Nitrogen injection is one of the emerging EOR technologies that is receiving serious attention most recently among various EOR methods. In general, the choice of the EOR method and the expected recovery depends on many considerations, economic as well as technical. In this paper, Nitrogen gas injection for reservoir enhanced oil recovery is discussed and compared with other available methods. Nitrogen injection provides an emerging opportunity for the cryogenics industry to adopt latest developments in this field for cost effective utilization of N2 injection in reservoirs, thus its establishment as a competitive enhanced oil recovery technique. While the present paper does not intend to get into technical details and the challenges involved in a typical cycle, it does provide an introduction of an important emerging application for the cryogenics industry, its comparison with other EOR techniques and the challenges involved. Review of previous research, including implementation projects on Nitrogen injection for EOR purposes on a global level is also discussed.

Units: Dual