Air injection LTO process: an IOR technique for light-oil reservoirs

S R Ren, M Greaves, R R Rathbone

Research output: Contribution to journalArticlepeer-review

99 Citations (Scopus)

Abstract

The paper describes an air injection improved oil recovery (IOR) process for the recovery of residual oil from light-oil reservoirs. Unlike the air injection technique applied in heavy-oil reservoirs, the main concern for a light-oil reservoir is to remove the oxygen from the injected air by some kind of spontaneous reaction between the oil and oxygen. In-situ combustion in heavy oil reservoirs is a very effective reaction pathway to achieve complete oxygen consumption, as well as to generate heat for enhanced oil recovery. For deep light-oil reservoirs, in-situ combustion is not necessary and may not be readily sustained. More likely, so-called low temp. oxidn. (LTO) will prevail. In this study, the potential for LTO reactions to consume oxygen, the reaction rate, and the reaction pathways are investigated. A simplified LTO reaction model has been established based on exptl. data obtained from a batch reactor expt. The model was validated against high-pressure flow displacement expts. in an oxidn. tube. A scoping simulation study on a reservoir scale has enabled a sensitivity assessment of the process to be made. The effect of air injection rate, reservoir dip, oil viscosity, formation permeability, numerical grid size, and reservoir temp. on oil recovery and the thermal effect were investigated. Compared with what is normally understood to be conventional air injection (in-situ combustion), the air injection LTO process is flexible in terms of injection rate, stable because of spontaneous reaction (if the reservoir temp. is high enough), and also an economic alternative to hydrocarbon, nitrogen, or carbon dioxide gas. It can also be used as a secondary recovery method in reservoirs that are not suitable for water injection. [on SciFinder (R)]
Original languageEnglish
Pages (from-to)90-99
Number of pages10
JournalSPE Journal (Society of Petroleum Engineers)
Volume7
Issue number1
Publication statusPublished - 2002

Keywords

  • Petroleum recovery (improved residual oil recovery from light-oil reservoirs using air injection)
  • petroleum recovery air injection oxidn
  • Oxidation (low-temp.
  • improved residual oil recovery from light-oil reservoirs using air injection)

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