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The Scientific World Journal
Volume 2014, Article ID 309159, 12 pages
Review Article

Microbial Enhanced Heavy Oil Recovery by the Aid of Inhabitant Spore-Forming Bacteria: An Insight Review

1Department of Biology, College of Science, Sultan Qaboos University, 123 Muscat, Oman
2Petroleum and Chemical Engineering Department, College of Engineering, Sultan Qaboos University, 123 Muscat, Oman
3Central Analytical and Applied Research Unit, College of Science, Sultan Qaboos University, 123 Muscat, Oman

Received 28 August 2013; Accepted 20 October 2013; Published 16 January 2014

Academic Editors: Z. He, A. Piacentino, and H. Tsutsumi

Copyright © 2014 Biji Shibulal et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Crude oil is the major source of energy worldwide being exploited as a source of economy, including Oman. As the price of crude oil increases and crude oil reserves collapse, exploitation of oil resources in mature reservoirs is essential for meeting future energy demands. As conventional recovery methods currently used have become less efficient for the needs, there is a continuous demand of developing a new technology which helps in the upgradation of heavy crude oil. Microbial enhanced oil recovery (MEOR) is an important tertiary oil recovery method which is cost-effective and eco-friendly technology to drive the residual oil trapped in the reservoirs. The potential of microorganisms to degrade heavy crude oil to reduce viscosity is considered to be very effective in MEOR. Earlier studies of MEOR (1950s) were based on three broad areas: injection, dispersion, and propagation of microorganisms in petroleum reservoirs; selective degradation of oil components to improve flow characteristics; and production of metabolites by microorganisms and their effects. Since thermophilic spore-forming bacteria can thrive in very extreme conditions in oil reservoirs, they are the most suitable organisms for the purpose. This paper contains the review of work done with thermophilic spore-forming bacteria by different researchers.