Microbial enhanced oil recovery
The first production from an oil well is the result of the pressure either of the pressure of earth’s overburden on the oil-bearing formation, or by pumping to create negative pressure. As this primary production declines, some oil wells are converted to injector wells, and either waterflooding or sometimes gas flooding are implemented. Even after this secondary production effort has reached its economic limit, two-thirds of the original oil in place is still left in the ground and tertiary measures may be employed. These include chemical enhanced oil recovery (EOR) methods such as polymer flooding, surfactant flooding, alkaline flooding, etc. or the use of thermal measures such as injection of steam or in situ combustion.
Another tertiary method of oil recovery is microbial enhanced oil recovery, commonly referred to as MEOR. There are several ways in which microorganisms can enhance oil recovery other than what is commonly referred to as MEOR. Microorganisms can be used to reduce the paraffin build-up in producing wells or they can be utilized to produce solvents or polymers above ground for pumping into the oil-bearing formation as in EOR. In reality, the difference between EOR and some of the MEOR methods is the means by which the recovery-enhancing chemicals are introduced into the reservoir. Normally however, MEOR refers to the use of microorganisms in the oil-bearing formation itself to enhance oil recovery.
Since 1946 more than 400 patents on MEOR have been issued, but none has gained acceptance by the oil industry. Most of the literature on MEOR is from laboratory experiments or from field trials of insufficient duration or that lack convincing proof of the process. Several authors have made recommendations required to establish MEOR as a viable method to enhance oil recovery, and until these tests are performed, MEOR will remain an unproven concept rather than a highly desirable reality.
Microbial enhanced oil recovery (MEOR). Curr Opin Microbiol. Feb 8 2010
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Tags: Bacteria, Biology, Biotechnology, energy, Environment, Microbiology, Science
