World Journal of Microbiology and Biotechnology, 2021
The Role of microorganisms in the petroleum industry is wide-ranging. To understand the role of m... more The Role of microorganisms in the petroleum industry is wide-ranging. To understand the role of microorganisms in hydrocarbon transformation, identification of such microorganisms is vital, especially the ones capable of in situ degradation. Microorganisms play a pivotal role in the degradation of hydrocarbons and remediation of heavy metals. Anaerobic microorganisms such as Sulphate Reducing Bacteria (SRB), responsible for the production of hydrogen sulphide (H2S) within the reservoir, reduces the oil quality by causing reservoir souring and reduction in oil viscosity. This paper reviews the diversity of SRB, methanogens, Nitrogen Reducing Bacteria (NRB), and fermentative bacteria present in oil reservoirs. It also reviews the extensive diversity of these microorganisms, their applications in petroleum industries, characteristics and adaptability to survive in different conditions, the potential to alter the petroleum hydrocarbons properties, the propensity to petroleum hydrocarbon degradation, and remediation of metals.
Large volumes of water are produced (PW) during oil and gas production from the various oil field... more Large volumes of water are produced (PW) during oil and gas production from the various oil fields of Upper Assam Basin, India. PW is a very complex mixture and contains different toxic compounds that adversely affect the surrounding environment, the reservoir environment and also the economics of oil and gas production. PW separated from oil and gas is either injected into the reservoir for pressure maintenance or discharged to the environment. Therefore evaluation of PW and its characterization is very important and essential for environment and reservoir management. This study deals with the complete evaluation and characterization of PW generated from different depths and horizons of oil reservoirs. The evaluation included the analysis of pH, specific gravity, salinity, total dissolved solids (TDS), cations, anions, organics and minerals. The values of specific gravity, salinity, TDS, and some ions such as sodium and chloride of oilfield PW were increased with increasing the reservoir depths. Useful relationships were observed between salinity, TDS, cations, anions, organics and minerals. These results can be used in the design, operation, and optimization of wastewater treatment systems of petroleum industries for future studies.
Enhanced Oil Recovery (EOR) techniques are becoming the thrust area to recover the residual oil i... more Enhanced Oil Recovery (EOR) techniques are becoming the thrust area to recover the residual oil in most of the matured depleted reservoirs. The microscopic displacement efficiency (ED) of chemical Enhanced Oil Recovery (CEOR) particularly surfactant and/or alkali are dependent on the interfacial properties between the reservoir fluids, mainly crude oil and formation water. This paper discusses the details of all the results of the laboratory experiments carried out to develop an alkali-surfactant (A-S) EOR slug for two depleted oil fields of Barail formation of Upper Assam. A series of experiments such as IFT, adsorption study, compatibility study and thermal stability have been carried out to optimize an A-S formulation. Depending on the anionic nature of most reservoirs of Upper Assam, an anionic surfactant system comprising of a natural surfactant ‘black liquor (BL)’ and a synthetic surfactant ‘Sodium Dodecyl Sulfate (SDS)’ was adopted. This system at its critical micellar concentration (CMC) was mixed with alkalis: Na2CO3 and NaHCO3 and corresponding CMC values at the lowest IFT were recorded. IFT experiments conducted separately with formation water (containing K+, Ca2+, Mg2+) and with laboratory prepared brine (containing Na+ only) established that IFT values are lower with formation water than that with the later. This study conducted in the temperature range from 30 °C to 80 °C showed that IFTs increase slightly with temperature, but within the range under study, temperature did not appear to have significant effect on IFT. Based on IFT reducing capabilities, a slug comprising of BL, SDS and Na2CO3 was selected for the EOR application in the considered depleted oil fields.
World Journal of Microbiology and Biotechnology, 2021
The Role of microorganisms in the petroleum industry is wide-ranging. To understand the role of m... more The Role of microorganisms in the petroleum industry is wide-ranging. To understand the role of microorganisms in hydrocarbon transformation, identification of such microorganisms is vital, especially the ones capable of in situ degradation. Microorganisms play a pivotal role in the degradation of hydrocarbons and remediation of heavy metals. Anaerobic microorganisms such as Sulphate Reducing Bacteria (SRB), responsible for the production of hydrogen sulphide (H2S) within the reservoir, reduces the oil quality by causing reservoir souring and reduction in oil viscosity. This paper reviews the diversity of SRB, methanogens, Nitrogen Reducing Bacteria (NRB), and fermentative bacteria present in oil reservoirs. It also reviews the extensive diversity of these microorganisms, their applications in petroleum industries, characteristics and adaptability to survive in different conditions, the potential to alter the petroleum hydrocarbons properties, the propensity to petroleum hydrocarbon degradation, and remediation of metals.
Large volumes of water are produced (PW) during oil and gas production from the various oil field... more Large volumes of water are produced (PW) during oil and gas production from the various oil fields of Upper Assam Basin, India. PW is a very complex mixture and contains different toxic compounds that adversely affect the surrounding environment, the reservoir environment and also the economics of oil and gas production. PW separated from oil and gas is either injected into the reservoir for pressure maintenance or discharged to the environment. Therefore evaluation of PW and its characterization is very important and essential for environment and reservoir management. This study deals with the complete evaluation and characterization of PW generated from different depths and horizons of oil reservoirs. The evaluation included the analysis of pH, specific gravity, salinity, total dissolved solids (TDS), cations, anions, organics and minerals. The values of specific gravity, salinity, TDS, and some ions such as sodium and chloride of oilfield PW were increased with increasing the reservoir depths. Useful relationships were observed between salinity, TDS, cations, anions, organics and minerals. These results can be used in the design, operation, and optimization of wastewater treatment systems of petroleum industries for future studies.
Enhanced Oil Recovery (EOR) techniques are becoming the thrust area to recover the residual oil i... more Enhanced Oil Recovery (EOR) techniques are becoming the thrust area to recover the residual oil in most of the matured depleted reservoirs. The microscopic displacement efficiency (ED) of chemical Enhanced Oil Recovery (CEOR) particularly surfactant and/or alkali are dependent on the interfacial properties between the reservoir fluids, mainly crude oil and formation water. This paper discusses the details of all the results of the laboratory experiments carried out to develop an alkali-surfactant (A-S) EOR slug for two depleted oil fields of Barail formation of Upper Assam. A series of experiments such as IFT, adsorption study, compatibility study and thermal stability have been carried out to optimize an A-S formulation. Depending on the anionic nature of most reservoirs of Upper Assam, an anionic surfactant system comprising of a natural surfactant ‘black liquor (BL)’ and a synthetic surfactant ‘Sodium Dodecyl Sulfate (SDS)’ was adopted. This system at its critical micellar concentration (CMC) was mixed with alkalis: Na2CO3 and NaHCO3 and corresponding CMC values at the lowest IFT were recorded. IFT experiments conducted separately with formation water (containing K+, Ca2+, Mg2+) and with laboratory prepared brine (containing Na+ only) established that IFT values are lower with formation water than that with the later. This study conducted in the temperature range from 30 °C to 80 °C showed that IFTs increase slightly with temperature, but within the range under study, temperature did not appear to have significant effect on IFT. Based on IFT reducing capabilities, a slug comprising of BL, SDS and Na2CO3 was selected for the EOR application in the considered depleted oil fields.
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