Analysis of Bacterial Diversity in Different Heavy Oil Wells of a Reservoir in South Oman with Alkaline pH

Abstract

The identification of potential hydrocarbon utilizing bacteria is an essential requirement in microbial enhanced oil recovery (MEOR). Molecular approaches like proteomic and genomic characterization of the isolates are replacing the traditional method of identification with systemic classification. Genotypic profiling of the isolates includes fingerprint or pattern-based technique and sequence-based technique. Understanding community structure and dynamics is essential for studying diversity profiles and is challenging in the case of microbial analysis. The present study aims to understand the bacterial community composition from different heavy oil contaminated soil samples collected from geographically related oil well areas in Oman and to identify spore-forming hydrocarbon utilizing cultivable bacteria. V4 region of 16S rDNA gene was the target for Ion PGM™. A total of 825081 raw sequences were obtained from Ion torrent from all the 10 soil samples. The species richness and evenness were found to be moderate in all the samples with four main phyla, Firmicutes, Bacteroidetes, Proteobacteria, and Actinobacteria, the most abundant being Firmicutes. Bacillus sp. ubiquitously dominated in all samples followed by Paenibacillus, which was followed by Brevibacillus, Planococcus, and Flavobacterium. Principal Coordinate Analysis (PCoA) and UPGMA dendrogram clustered the 10 soil samples into four main groups. Weighted UniFrac significance test determined that there was significant difference in the communities present in soil samples examined. It can be concluded that the microbial community was different in all the 10 soil samples with Bacillus and Paenibacillus sp. as predominating genus. The 16S rDNA sequencing of cultivable spore-forming bacteria identified the hydrocarbon utilizing bacteria as Bacillus and Paenibacillus sp. and the nucleotide sequences were submitted to NCBI GenBank under accession numbers KP119097–KP119115. Bacillus and Paenibacillus sp., which were relatively abundant in the oil fields, can be recommended to be chosen as candidates for hydrocarbon utilization study.

Uses of Microorganisms in The Recovery of Oil and Gas

“…When both primary and secondary recuperation techniques have been applied, it is thought that MEOR can recover up to fifty percent of the remaining oil in a pond. Metabolite production and growing bacteria to achieve this increased recovery typically include changing the physical and chemical attributes petroleum products and deposit rocks [1]. As a result, MEOR could overcome the fundamental barriers to effective oil regeneration, High crude oil stiffness, poor aquifer accessibility, and maximum oil IFTs, for example, provide flow resistance strong enough to trap the oil in the pores of the reservoir rock.…”

“…Certain Bacillus strains are extremely successful because they can produce biosurfactants that promote the MEOR process in situ [8]. To stimulate microbial metabolism, nutrients, most often in the form of fermentable carbohydrates, are administered [1]. Clostridium acetobutylicum morphological and cytological alterations during the formation of acetone, butanol, and ethanol in an industrial fermentation medium were found and linked with growth and physiological changes.…”

“…While crude oil's dissolved gases and solvents may reduce viscosity, secondary metabolites can dissolve carbonate rocks, raising reservoir permeability [15]. Table (1) summarises these bioproducts and their related technologies.…”

“…Despite the fact that coal and oil (oil, gas, and coal) will eventually overtake energy sources, contributing for more than three-quarters of global energy infrastructure in 2035, demand for renewables will surge (such as nuclear, solar, and wind) as well as desire for geothermal, wave, and biofuels has increased concurrently. Secondary oil recovery can boost recovery by 15-25%, and up to 55% remaining unrecoverable in petroleum reservoirs [1].The industry is motivated to maximize oil recovery efficiency by the current low but volatile oil price, the maturation of major oil fields (such as the North Sea) and the decline in the number of freshly produced oil fields [2]. EOR is a tertiary recovery technique which employs diverse thermo, biochemical, and microbiological techniques to recover a supplemental 7-15percent of the overall of oil from underperforming and depleted oil wells at an efficient and cost-effective production rate [3].…”

Utilization of lignocellulosic biomass: A practical journey towards the development of emulsifying agent

“…That method enhanced the recovery of the entrapped crude oil by efficiently improving the primary and secondary extraction techniques. The water injected into the oil reservoir to displace the oil did not penetrate the area with high permeability and thus circumvented most of the oil trapped here [39]. The emulsified oil droplets mobilized before were entrapped in pores with high permeability, thus forcing the flow of water through them.…”