Both light-oil air injection (LOAI) and nitrogen injection have received considerable attention recently due to several successful LOAI projects and the building of massive nitrogen generation plants for offshore EOR. This paper explores the advantages of combining the best of both technologies via cogeneration of nitrogen and rich air for use in adjacent reservoirs.

Rich air (30% to 40% oxygen) can be an alternative to carbon dioxide injection just as air injection is generally practiced where carbon dioxide is not available. Rich air is the byproduct of nitrogen generation and has approximately the same price as nitrogen, yet it will recover more oil because of the higher solubility of the carbon dioxide that is produced by in-situ oxidation of the oil.

Not only can the rich air be used for light-oil production, but also it can be a more efficient way to produce energy from heavy-oil through wet combustion in deeper reservoirs. Examples contained herein illustrate how nitrogen and rich air can be used in both light- and heavy-oil reservoirs.

Keywords:
gas injection method, co 2, nitrogen, oxygen, injection, producer, upstream oil & gas, viscosity, rich air, flue gas
Subjects:
Improved and Enhanced Recovery, Gas-injection methods
Copyright 2004, Society of Petroleum Engineers
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