Crude oil spills have inflicted extensive disruption upon the Niger Delta ecosystem, resulting in crop loss and severe environmental damage. Such spills exacerbate heavy metal concentration within soil due to the pres...Crude oil spills have inflicted extensive disruption upon the Niger Delta ecosystem, resulting in crop loss and severe environmental damage. Such spills exacerbate heavy metal concentration within soil due to the presence of metallic ions. The Okpare-Olomu community has borne the brunt of crude oil pollution from illicit bunkering, sabotage, and equipment malfunction. This study targets an evaluation of ecological hazards linked to heavy metals (HMs) in crude oil impacted agriculturally soils within Okpare-Olomu in Ughelli South LGA of Delta State. In this study, 24 topsoil samples were obtained from areas affected by crude oil pollution;the heavy metal content was evaluated through atomic absorption spectrometry. The concentration ranges for HMs (mg/kg) in soil were: 24.1 - 23,174 (Cu);0.54 - 37.1 (Cd);9.05 - 54 (Cr);12 - 174 (Ni);18.5 - 8611 (Pb);and 148 - 9078 (Zn) at a soil depth of 0 - 15 cm. Notably, metal concentrations were recorded to be above permissible World Health Organization limits. Predominantly, Zn and Pb recorded higher heavy metal concentration when compared to other heavy metals analysed, notably at sampling points PT7 through PT24. Zinc and Pb contamination exhibited highly significant contamination factors, and contamination severity was evidenced across all sample points, signifying a grave risk level. Pollution load indices indicated pervasive extreme pollution levels. Geoaccumulation indices signaled moderate to strong pollution, mainly by Pb and Zn. Ecological risk assessments revealed variable levels of heavy metal contamination, from low to very high, with potential ecological risk reflecting markedly elevated levels. This study underscores the imperative for soil remediation to rectify ecological imbalances in agriculturally affected soil constituents.展开更多
Most heavy crude oils underwent biodegradation and generated a significant amount of naphthenic acids. Naphthenic acids are polar compounds with the carboxylic group and are considered as a major factor affecting the ...Most heavy crude oils underwent biodegradation and generated a significant amount of naphthenic acids. Naphthenic acids are polar compounds with the carboxylic group and are considered as a major factor affecting the oil viscosity. However, the relationship between the molecular composition of naphthenic acids and oil viscosity is not well understood. This study examined a “clean” heavy oil with low contents of heteroatoms but had a high content of naphthenic acids. Naphthenic acids were fractionated by distillation and caustic extraction. The molecular composition was characterized by high-resolution Orbitrap mass spectrometry. It was found that the 2- and 3-ring naphthenic monoacids with 15–35 carbon atoms are dominant components of the acid fractions;the caustic extraction is capable of isolating naphthenic acids with less than 35 carbons, which is equivalent to the upper limit of the distillable components, but not those in the residue fraction;the total acid number of the heavy distillates is higher than that of the residue fraction;the viscosity of the distillation fraction increases exponentially with an increased boiling point of the distillates. Blending experiments indicates that there is a strong correlation between the oil viscosity and acids content, although the acid content is only a few percent of the total oil.展开更多
The process of transporting crude oil across pipelines is one of the most critical aspects of the midstream petroleum industry.In the present experimental work,the effect of temperature,pressure drop,and pipe diameter...The process of transporting crude oil across pipelines is one of the most critical aspects of the midstream petroleum industry.In the present experimental work,the effect of temperature,pressure drop,and pipe diameter on the flow rate of heavy crude oil have been assessed.Moreover,the total discharge and energy losses have been evaluated in order to demonstrate the improvements potentially achievable by using solar heating method replacing pipe,and adjusting the value of the initial pressure difference.Crude oil of API=20 has been used for the experiments,with the studied pipelines sections connecting the separator unit to the storage tank operating at a temperature of 25℃-100℃,pressure drop of 3,4,5,and 6 kg/cm^(2),and with pipe diameter of 4,6,and 8 in.The results show that on increasing the temperature and/or the pressure drop,the flow rate through the pipeline becomes higher,thus raising the total pumping energy(as the pipe diameter increase),while energy losses increase from the last separator to the storage tank in the field.A pipe diameter increase can also produce a growth of the total pumping energy(i.e.,energy losses increase).The results of the present analysis suggest that employing an optimal temperature(50℃)is needed to ensure good performance.展开更多
The most economical way to overcome flow assurance problems associated with transportation of heavy crude oil through offshore pipelines is by emulsifying it with water in the presence of a suitable surfactant.In this...The most economical way to overcome flow assurance problems associated with transportation of heavy crude oil through offshore pipelines is by emulsifying it with water in the presence of a suitable surfactant.In this research,a novel surfactant,tri-triethanolamine monosunflower ester,was synthesized in the laboratory by extracting fatty acids present in sunflower（Helianthus annuus）oil.Synthesized surfactant was used to prepare oil-in-water emulsions of a heavy crude oil from the western oil field of India.After emulsification,a dramatic decrease in pour point as well as viscosity was observed.All the prepared emulsions were found to be flowing even at 1°C.The emulsion developed with 60%oil content and 2wt%surfactant showed a decrease in viscosity of 96%.The stability of the emulsion was investigated at different temperatures,and it was found to be highly stable.The effectiveness of surfactant in emulsifying the heavy oil in water was investigated by measuring the equilibrium interfacial tension（IFT）between the crude oil（diluted）and the aqueous phase along with zeta potential of emulsions.2wt%surfactant decreased IFT by almost nine times that of no surfactant.These results suggested that the synthesized surfactant may be used to prepare a stable oil-in-water emulsion for its transportation through offshore pipelines efficiently.展开更多
The main problem of new crude oil reserves is the incipient increase of heavy crude oils in the American continent, i.e. USA, Mexico, Canada and Venezuela. These types of crude oils require several treatments before r...The main problem of new crude oil reserves is the incipient increase of heavy crude oils in the American continent, i.e. USA, Mexico, Canada and Venezuela. These types of crude oils require several treatments before refining. One of these treatments can be hydrocracking. In this petroleum refining process, it is possible to modify the heavy crude oils to light crude oils. In this paper, we try to use hydrocracking to improve the quality of raw heavy crude oil, through some chemical transformations C-H binding rupture using a catalyst containing active metals such as tungsten and zirconium (W-Zr). After the crude oil was hydrocracked in presence of this novel bimetallic catalyst, the hydrocracked products showed lower content of asphaltenes, resins, sulfur and nitrogen. Also positive changes in the viscosity of crude oil measured as a decreasing of this value were observed. The American Petroleum Institute (API) gravity was significantly increased 6 units. Consequently, all these changes confirmed that the upgrading of the heavy crude oil was successful.展开更多
Multiple biostimulation treatments were applied to enhance the removal of heavy crude oil pollutants in the saline soil of Yellow River Delta.Changes of the soil bacterial community were monitored using the terminal r...Multiple biostimulation treatments were applied to enhance the removal of heavy crude oil pollutants in the saline soil of Yellow River Delta.Changes of the soil bacterial community were monitored using the terminal restriction fragment length polymorphism （T-RFLP） and clone library analyses.The 140-day microcosm experiments showed that low C：N：P ratio,high availability of surfactant and addition of bulking agent significantly enhanced the performance,leading to the highest total petroleum hydrocarbon removal.Meanwhile,the bacterial community was remarkably changed by the multiple biostimulation treatments,with the Deltaproteobacteria,Firmicutes,Actinobacteria,Acidobacteria and Planctomycetes being inhibited and the Alphaand Beta-proteobacteria and some unknown Gammaproteobacteria bacteria being enriched.In addition,different hydrocarbon-degraders came to power in the following turn.At the first stage,the Alcanivorax-related Gammaproteobacteria bacteria dominated in the biostimulated soil and contributed mainly to the biodegradation of easily degradable portion of the heavy crude oil.Then the bacteria belonging to Alphaproteobacteria,followed by bacteria belonging to Candidate division OD1,became the dominant oil-degraders to degrade the remaining recalcitrant constituents of the heavy crude oil.展开更多
The effects of water content, shear rate, temperature, and solid particle concentration on viscosity reduction （VR） caused by forming stable emulsions were investigated using Omani heavy crude oil. The viscosity of ...The effects of water content, shear rate, temperature, and solid particle concentration on viscosity reduction （VR） caused by forming stable emulsions were investigated using Omani heavy crude oil. The viscosity of the crude oil was initially measured with respect to shear rates at different temperatures from 20 to 70℃. The crude oil exhibited a shear thinning behavior at all the temperatures. The strongest shear thinning was observed at 20℃. A non-ionic water soluble surfactant （Triton X-100） was used to form and stabilize crude oil emulsions. The emulsification process has significantly reduced the crude oil viscosity. The degree of VR was found to increase with an increase in water content and reach its maximum value at 50 % water content. The phase inversion from oil- oil emulsion occurred at 30 in-water emulsion to water-in- % water content. The results indicated that the VR was inversely proportional to temperature and concentration of silica nanoparticles. For water-in-oil emulsions, VR increased with shear rate and eventually reached a plateau at a shear rate of around 350 s^-1. This was attributed to the thinning behavior of the continuous phase. The VR of oil-in-water emulsions remained almost constant as the shear rate increased due to the Newtonian behavior of water, the continuous phase.展开更多
Given the combination of rising global energy demand and the decline in conventional crudes, heavycrudes are generally considered to be the future energy resource. In many regions of the world, heavycrude oil must be ...Given the combination of rising global energy demand and the decline in conventional crudes, heavycrudes are generally considered to be the future energy resource. In many regions of the world, heavycrude oil must be transported through pipelines from the point of production to storage facilities orrefineries. The transportation of heavy crude oil by pipeline poses serious problems related to the highviscosity and flow difficulties, particularly in cold climates or offshore conditions. Indeed, the viscosity ofcrude oil is an important physical property that influences and controls crude oil flow in pipelines.Viscosity introduces resistance to movement by causing a shear or frictional force between the fluidparticles and the boundary walls. This high viscosity means that the pumping power requirements forcrude oil in a long-distance pipeline are very high in order to overcome the increasing shear and frictionforces. Therefore, in order to facilitate the pumping of these viscous oils and reduce operating expensesand the negative impact of pressure drops in pipelines during flow and processing, their viscosity mustbe reduced. Various techniques are used to increase pumping efficiency and improve the flow of crude oilthrough the pipeline, which may present logistical, technical or economic disadvantages for a givenapplication. The main ones are the addition of surfactants or polymers, dilution with lighter crudes, useof water as annular fluid, thermal remediation and emulsification with surfactant (O/W). This reviewhighlights the methods currently used to enhance the fluidity of heavy crude oil in pipelines behindrheology improvement, in particular the addition of additives and the use of water and surfactants tocreate a stable emulsion of heavy crude oil in water have been considered.展开更多
The origins and logging responses of flushed zones in some blocks of Orinoco heavy oil belt, Venezuela are still unclear. To solve this issue, we examined the conventional logging, nuclear magnetic resonance logging, ...The origins and logging responses of flushed zones in some blocks of Orinoco heavy oil belt, Venezuela are still unclear. To solve this issue, we examined the conventional logging, nuclear magnetic resonance logging, fluid viscosity, core analysis and oil field production data comprehensively to find out the logging responses and origins of the flushed zones. The results show that the main reason for the formation of flushed zone is surface water invasion, which leads to crude oil densification. The crude oil densification produces asphalt membrane(asphalt crust) which wraps up free water, causing special logging responses of the flushed zones. According to the different logging responses, we classified the flushed zones into two types and analyzed the formation processes of the two types of flushed zones. According to the characteristics of logging curves after water flush, we confirmed that the water flush began earlier than the reservoir accumulation.展开更多
文摘Crude oil spills have inflicted extensive disruption upon the Niger Delta ecosystem, resulting in crop loss and severe environmental damage. Such spills exacerbate heavy metal concentration within soil due to the presence of metallic ions. The Okpare-Olomu community has borne the brunt of crude oil pollution from illicit bunkering, sabotage, and equipment malfunction. This study targets an evaluation of ecological hazards linked to heavy metals (HMs) in crude oil impacted agriculturally soils within Okpare-Olomu in Ughelli South LGA of Delta State. In this study, 24 topsoil samples were obtained from areas affected by crude oil pollution;the heavy metal content was evaluated through atomic absorption spectrometry. The concentration ranges for HMs (mg/kg) in soil were: 24.1 - 23,174 (Cu);0.54 - 37.1 (Cd);9.05 - 54 (Cr);12 - 174 (Ni);18.5 - 8611 (Pb);and 148 - 9078 (Zn) at a soil depth of 0 - 15 cm. Notably, metal concentrations were recorded to be above permissible World Health Organization limits. Predominantly, Zn and Pb recorded higher heavy metal concentration when compared to other heavy metals analysed, notably at sampling points PT7 through PT24. Zinc and Pb contamination exhibited highly significant contamination factors, and contamination severity was evidenced across all sample points, signifying a grave risk level. Pollution load indices indicated pervasive extreme pollution levels. Geoaccumulation indices signaled moderate to strong pollution, mainly by Pb and Zn. Ecological risk assessments revealed variable levels of heavy metal contamination, from low to very high, with potential ecological risk reflecting markedly elevated levels. This study underscores the imperative for soil remediation to rectify ecological imbalances in agriculturally affected soil constituents.
基金supported by the National Key R&D Program of China(2018YFA0702400)Science Foundation of China University of Petroleum,Beijing(ZX20210029).
文摘Most heavy crude oils underwent biodegradation and generated a significant amount of naphthenic acids. Naphthenic acids are polar compounds with the carboxylic group and are considered as a major factor affecting the oil viscosity. However, the relationship between the molecular composition of naphthenic acids and oil viscosity is not well understood. This study examined a “clean” heavy oil with low contents of heteroatoms but had a high content of naphthenic acids. Naphthenic acids were fractionated by distillation and caustic extraction. The molecular composition was characterized by high-resolution Orbitrap mass spectrometry. It was found that the 2- and 3-ring naphthenic monoacids with 15–35 carbon atoms are dominant components of the acid fractions;the caustic extraction is capable of isolating naphthenic acids with less than 35 carbons, which is equivalent to the upper limit of the distillable components, but not those in the residue fraction;the total acid number of the heavy distillates is higher than that of the residue fraction;the viscosity of the distillation fraction increases exponentially with an increased boiling point of the distillates. Blending experiments indicates that there is a strong correlation between the oil viscosity and acids content, although the acid content is only a few percent of the total oil.
文摘The process of transporting crude oil across pipelines is one of the most critical aspects of the midstream petroleum industry.In the present experimental work,the effect of temperature,pressure drop,and pipe diameter on the flow rate of heavy crude oil have been assessed.Moreover,the total discharge and energy losses have been evaluated in order to demonstrate the improvements potentially achievable by using solar heating method replacing pipe,and adjusting the value of the initial pressure difference.Crude oil of API=20 has been used for the experiments,with the studied pipelines sections connecting the separator unit to the storage tank operating at a temperature of 25℃-100℃,pressure drop of 3,4,5,and 6 kg/cm^(2),and with pipe diameter of 4,6,and 8 in.The results show that on increasing the temperature and/or the pressure drop,the flow rate through the pipeline becomes higher,thus raising the total pumping energy(as the pipe diameter increase),while energy losses increase from the last separator to the storage tank in the field.A pipe diameter increase can also produce a growth of the total pumping energy(i.e.,energy losses increase).The results of the present analysis suggest that employing an optimal temperature(50℃)is needed to ensure good performance.
基金the Indian Institute of Technology (Indian School of Mines), Dhanbad for providing necessary laboratory facilities and financial support
文摘The most economical way to overcome flow assurance problems associated with transportation of heavy crude oil through offshore pipelines is by emulsifying it with water in the presence of a suitable surfactant.In this research,a novel surfactant,tri-triethanolamine monosunflower ester,was synthesized in the laboratory by extracting fatty acids present in sunflower（Helianthus annuus）oil.Synthesized surfactant was used to prepare oil-in-water emulsions of a heavy crude oil from the western oil field of India.After emulsification,a dramatic decrease in pour point as well as viscosity was observed.All the prepared emulsions were found to be flowing even at 1°C.The emulsion developed with 60%oil content and 2wt%surfactant showed a decrease in viscosity of 96%.The stability of the emulsion was investigated at different temperatures,and it was found to be highly stable.The effectiveness of surfactant in emulsifying the heavy oil in water was investigated by measuring the equilibrium interfacial tension（IFT）between the crude oil（diluted）and the aqueous phase along with zeta potential of emulsions.2wt%surfactant decreased IFT by almost nine times that of no surfactant.These results suggested that the synthesized surfactant may be used to prepare a stable oil-in-water emulsion for its transportation through offshore pipelines efficiently.
文摘The main problem of new crude oil reserves is the incipient increase of heavy crude oils in the American continent, i.e. USA, Mexico, Canada and Venezuela. These types of crude oils require several treatments before refining. One of these treatments can be hydrocracking. In this petroleum refining process, it is possible to modify the heavy crude oils to light crude oils. In this paper, we try to use hydrocracking to improve the quality of raw heavy crude oil, through some chemical transformations C-H binding rupture using a catalyst containing active metals such as tungsten and zirconium (W-Zr). After the crude oil was hydrocracked in presence of this novel bimetallic catalyst, the hydrocracked products showed lower content of asphaltenes, resins, sulfur and nitrogen. Also positive changes in the viscosity of crude oil measured as a decreasing of this value were observed. The American Petroleum Institute (API) gravity was significantly increased 6 units. Consequently, all these changes confirmed that the upgrading of the heavy crude oil was successful.
基金supported by the International Cooperation Project of National Natural Science Foundation of China (No.40821140541)the National High Technology Research and Development Program (863) of China (No.2009AA063501)
文摘Multiple biostimulation treatments were applied to enhance the removal of heavy crude oil pollutants in the saline soil of Yellow River Delta.Changes of the soil bacterial community were monitored using the terminal restriction fragment length polymorphism （T-RFLP） and clone library analyses.The 140-day microcosm experiments showed that low C：N：P ratio,high availability of surfactant and addition of bulking agent significantly enhanced the performance,leading to the highest total petroleum hydrocarbon removal.Meanwhile,the bacterial community was remarkably changed by the multiple biostimulation treatments,with the Deltaproteobacteria,Firmicutes,Actinobacteria,Acidobacteria and Planctomycetes being inhibited and the Alphaand Beta-proteobacteria and some unknown Gammaproteobacteria bacteria being enriched.In addition,different hydrocarbon-degraders came to power in the following turn.At the first stage,the Alcanivorax-related Gammaproteobacteria bacteria dominated in the biostimulated soil and contributed mainly to the biodegradation of easily degradable portion of the heavy crude oil.Then the bacteria belonging to Alphaproteobacteria,followed by bacteria belonging to Candidate division OD1,became the dominant oil-degraders to degrade the remaining recalcitrant constituents of the heavy crude oil.
文摘The effects of water content, shear rate, temperature, and solid particle concentration on viscosity reduction （VR） caused by forming stable emulsions were investigated using Omani heavy crude oil. The viscosity of the crude oil was initially measured with respect to shear rates at different temperatures from 20 to 70℃. The crude oil exhibited a shear thinning behavior at all the temperatures. The strongest shear thinning was observed at 20℃. A non-ionic water soluble surfactant （Triton X-100） was used to form and stabilize crude oil emulsions. The emulsification process has significantly reduced the crude oil viscosity. The degree of VR was found to increase with an increase in water content and reach its maximum value at 50 % water content. The phase inversion from oil- oil emulsion occurred at 30 in-water emulsion to water-in- % water content. The results indicated that the VR was inversely proportional to temperature and concentration of silica nanoparticles. For water-in-oil emulsions, VR increased with shear rate and eventually reached a plateau at a shear rate of around 350 s^-1. This was attributed to the thinning behavior of the continuous phase. The VR of oil-in-water emulsions remained almost constant as the shear rate increased due to the Newtonian behavior of water, the continuous phase.
文摘Given the combination of rising global energy demand and the decline in conventional crudes, heavycrudes are generally considered to be the future energy resource. In many regions of the world, heavycrude oil must be transported through pipelines from the point of production to storage facilities orrefineries. The transportation of heavy crude oil by pipeline poses serious problems related to the highviscosity and flow difficulties, particularly in cold climates or offshore conditions. Indeed, the viscosity ofcrude oil is an important physical property that influences and controls crude oil flow in pipelines.Viscosity introduces resistance to movement by causing a shear or frictional force between the fluidparticles and the boundary walls. This high viscosity means that the pumping power requirements forcrude oil in a long-distance pipeline are very high in order to overcome the increasing shear and frictionforces. Therefore, in order to facilitate the pumping of these viscous oils and reduce operating expensesand the negative impact of pressure drops in pipelines during flow and processing, their viscosity mustbe reduced. Various techniques are used to increase pumping efficiency and improve the flow of crude oilthrough the pipeline, which may present logistical, technical or economic disadvantages for a givenapplication. The main ones are the addition of surfactants or polymers, dilution with lighter crudes, useof water as annular fluid, thermal remediation and emulsification with surfactant (O/W). This reviewhighlights the methods currently used to enhance the fluidity of heavy crude oil in pipelines behindrheology improvement, in particular the addition of additives and the use of water and surfactants tocreate a stable emulsion of heavy crude oil in water have been considered.
基金Supported by the China Major National Oil&Gas Project(2016ZX05031-001)
文摘The origins and logging responses of flushed zones in some blocks of Orinoco heavy oil belt, Venezuela are still unclear. To solve this issue, we examined the conventional logging, nuclear magnetic resonance logging, fluid viscosity, core analysis and oil field production data comprehensively to find out the logging responses and origins of the flushed zones. The results show that the main reason for the formation of flushed zone is surface water invasion, which leads to crude oil densification. The crude oil densification produces asphalt membrane(asphalt crust) which wraps up free water, causing special logging responses of the flushed zones. According to the different logging responses, we classified the flushed zones into two types and analyzed the formation processes of the two types of flushed zones. According to the characteristics of logging curves after water flush, we confirmed that the water flush began earlier than the reservoir accumulation.
