Oil and natural gas are vital for any economy and the importance of these resources in determining the social stability and economic viability of a nation is enormous. As the search for petroleum continues, recovery of known reserves must be improved if the goal of avoiding shortages is to be met. In today's energy sector, the high oil prices have driven the oil companies to recover the maximum amount of oil with the lowest production costs. Thus, economic production of oil and gas resources requires carefully engineered recovery projects of increasing technical complexity and sophistication.
One of the promising recovery methods is the microbiological enhanced oil recovery (MEOR). MEOR technology has the potential to be one of the reliable technologies that suits best the economic constraints of the current oil markets. The technology is a potential alternative to other EOR/ IOR methods, as it is being implementing in most parts of the world with satisfactory results not only form economics point of view but also from having lesser environmental impact.
The paper provides a review on MEOR technology and discusses it with special reference to marginal and/or uneconomical reserves. The goal of cost reduction, which is a major objective in any recovery methods, can be met by using MEOR technology which involves injecting a small amount of a solution containing microorganisms to spread through the reservoir and consequently produce desirable chemicals and gases that will enhance oil recovery and therefore profit. The paper also outlines the strategies to identify and meet the challenge of recovering large proportions of oil using MEOR techniques which could be very helpful in closing the energy gap by draining large proportions of oil which is left behind and minimizing the supply and demand difference in today's "energy hungry world".