Characterisation of culture-independent and -dependent microbial communities in a high-temperature offshore chalk petroleum reservoir

Abstract

Recent studies have indicated that oil reservoirs harbour diverse microbial communities. Culture-dependent and culture-independent methods were used to evaluate the microbial diversity in produced water samples of the Ekofisk oil field, a high temperature, and fractured chalk reservoir in the North Sea. DGGE analyses of 16S rRNA gene fragments were used to assess the microbial diversity of both archaeal and bacterial communities in produced water samples and enrichment cultures from 4 different wells (B-08, X-08, X-18 and X-25). Low diversity communities were found when 16S rDNA libraries of bacterial and archaeal assemblages were generated from total community DNA obtained from produced water samples and enrichment cultures. Sequence analysis of the clones indicated close matches to microbes associated with high-temperature oil reservoirs or other similar environments. Sequences were found to be similar to members of the genera Thermotoga, Caminicella, Thermoanaerobacter, Archaeoglobus, Thermococcus, and Methanobulbus. Enrichment cultures obtained from the produced water samples were dominated by sheathed rods. Sequence analyses of the cultures indicated predominance of the genera Petrotoga, Arcobacter, Archaeoglobus and Thermococcus. The communities of both produced water and enrichment cultures appeared to be dominated by thermophilic fermenters capable of reducing sulphur compounds. These results suggest that the biochemical processes in the Ekofisk chalk reservoir are similar to those observed in high-temperature sandstone reservoirs.

Molecular biologic techniques applied to the microbial prospecting of oil and gas in the Ban 876 gas and oil field in China

“…The cloning and sequencing of 16S rDNA is sufficient for the identification of the microorganisms present in a given habitat and for the discovery of previously unknown diversity (Hugenholtz et al 1998). These techniques were also applied to investigate microbial communities in the formation water of the produced water of oil fields (Kaster et al 2009;Lysnes et al 2009). However, analyzing microbial communities in soil samples in oil and gas fields for MPOG has seen less study.…”

Analysis of bacterial diversity and metals in produced water, seawater and sediments from an offshore oil and gas production platform

“…Compared to produced waters from other petroleum production regions like Hibernia (Yeung et al, in press), Terra Nova (Yeung et al, Unpublished results), and the North Sea (Kaster et al, 2009), the bacterial community structure in the produced water recovered from the discharge lines of the Thebaud platform was relatively simple with only four major bands detected by DGGE. The sequences from these bands were closely related to Acinetobacter spp.…”

“…and Geobacillus spp. These genera were not found in other produced waters from nearby regions (Yeung et al, Unpublished results;Kaster et al, 2009;Dahle et al, 2008), suggesting that the bacteria from the Thebaud produced water were unique to this produced water.…”

“…have also been isolated from oil fields in Saskatchewan, Canada (Gevertz et al, 2000), identified in a high-temperature offshore petroleum reservoir in the North Sea (Kaster et al, 2009) and detected in the Hibernia produced water discharge (Yeung et al, Unpublished results). Kaster et al (2009) also demonstrated that sequences similar to Arcobacter, a sulfur-compound oxidizing Epsilon-proteobacterium, were enriched in acetogenic and fermentative media at 55°C as well as fermentative and sulfate reducing media at 70°C. Arcobacter spp.…”

Microbial Techniques for Hydrocarbon Exploration

“…The cloning and sequencing of 16S rDNA is sufficient for the identification of the microorganisms present in a given habitat and for the discovery of previously unknown diversity (Hugenholtz et al 1998). These techniques were also applied to investigate microbial communities in the formation water of the produced water of oil fields (Kaster et al 2009;Lysnes et al 2009). Characterization of microbial communities involved in short-chain alkane metabolism, namely methane, ethane and propane, in soil samples from a petroliferous soils through clone libraries of the 16S rRNA gene of the Domains Bacteria and Archaea and the catabolic gene coding for the soluble di-iron monooxygenase (SDIMO) enzyme alpha subunit.…”