It is widely recognized that bacteria and archae are frequently contained within production fluids
and can cause numerous problems and cost countless dollars to the oil and gas industries. Current
techniques commonly employed to detect and enumerate these microorganisms and to test the efficacy
of microbiocides focus on serial dilution culture methods. Unfortunately, culture-dependent methods
allow for the growth of only a fraction of the field population present and do not support the growth of
numerous potentially significant species. Currently, it is estimated that less than 15% of field
populations can be cultivated by these means.
In this study, genetic profile analyses of microbial communities present in produced water
samples were compared to those that were derived from culturing that produced water using various
commonly used growth media. Genetic analyses utilized a 16S rRNA gene microarray which can
detect 8,741 OTUs (Operational Taxonomic Units) in a single test. As expected and in congruence with
samples from other environments, cultivation-dependent techniques greatly underestimated the
microbial diversity present. These results illustrate one of the fundamental problems of culturedependent
techniques: the large discrepancy between the microorganism population that is cultivated
and detected in culture mediums and the population that is actually present in the oil and gas field
environment.
KEYWORDS: Microbiologically-induced corrosion (MIC), Serial Dilution Culture Methods, Genetic
Profile Analysis, 16S rRNA Gene Microarray