Asphaltene deposition is one of the most seri- ous problems, which usually occurs in oil wells, petroleum production, oil processing, and transportation facilities. Deposition of heavy organic components, especially a...Asphaltene deposition is one of the most seri- ous problems, which usually occurs in oil wells, petroleum production, oil processing, and transportation facilities. Deposition of heavy organic components, especially asphaltene, can lead to wellbore blockage and impacts well economics due to reduction in oil production. Therefore, it is necessary to pay more attention to finding some solution to overcome this problem. In this study, a pipe-loop apparatus for investigation of oil stability was employed to measure deposition thickness using a thermal method. The effects of many factors such as oil type, oil temperature, oil velocity, inhibitors, and solvents on asphaltene deposition were investigated. The results showed that the deposition increased with the increasing value of the colloidal insta- bility index. Besides, the deposition thickness increased with the decreasing velocity of oil, but did not change with oil temperature. In addition, n-heptane could result in more deposition; however, toluene had no effect on the deposi- tion. Branched dodecyl benzene sulfonic acid （Branched DBSA） and Linear DBSA as inhibitors decreased the rate of asphaltene deposition.展开更多
One of the most severe problems during production from heavy crude oil reservoirs is the formation of asphaltene precipitation and as a result deposition in the tubing,surface facilities and near wellbore region which...One of the most severe problems during production from heavy crude oil reservoirs is the formation of asphaltene precipitation and as a result deposition in the tubing,surface facilities and near wellbore region which causes oil production and permeability reduction in addition to rock wettability alteration in the reservoir.So one of the economical ways to prevent such incidents is using the chemicals which are called asphaltene inhibitor.In this study,the influence of three commercial inhibitors,namely;Cetyl Terimethyl Ammonium Bromide(CTAB),Sodium Dodecyl Sulfate(SDS),Triton X-100 and four non-commercial(Benzene,Benzoic Acid,Salicylic Acid,Naphthalene)inhibitors on two Iranian crude oils were investigated.This study extends previous works and contributes toward the better understanding of interactions between asphaltene and inhibitor.Effect of functional groups and structure of inhibitors on asphaltene precipitation were studied and it seems clear that the nature and polarity of asphaltene(structure and amount of impurities presented)has a significant impact on the selection of inhibitors.asphaltene dispersant tests and Core flood tests were designed for evaluation of inhibitors in static and dynamic conditions.The results revealed distinguished mechanisms for asphaltene solubilization/dispersion(such as hydrogen bonding,pep interaction and acid-base interaction)and influence of additional side group(OH)on inhibition power of inhibitor.During the experiments,it was found that increasing inhibitor concentration may lead to the self-assembly of inhibitor and declining of asphaltene stabilization.So,finding optimum concentration of inhibitor with high efficiency and available at a reasonable price is very important.The results suggest that 600 ppm of CTAB and 300 ppm of SDS were approximately optimum concentrations for the studied crude oils.One of the most important findings that differ from previous studies is the revelation of the mechanism behind the SDS/asphaltene behavior in various concentrations of inhibitor.Effect of chosen inhibitors on asphaltene precipitation and consequently deposition in porous media was studied,and then experimental data were modeled for evaluation of permeability impairment mechanisms.Permeability revived after inhibitor squeezing and cake formation mechanism played an important role in permeability reduction before and after treatment in porous media.The findings can also be applied to prediction of future behavior of reservoirs in oil field scale and evaluation of formation damage in the different period of production if needed any treatment process.展开更多
By screening solvents and surfactants,a surfactant with strong wetting and dispersing ability has been discovered,which can form stable emulsions.An O/W emulsifier that can inhibit paraffin deposition and remove it ha...By screening solvents and surfactants,a surfactant with strong wetting and dispersing ability has been discovered,which can form stable emulsions.An O/W emulsifier that can inhibit paraffin deposition and remove it has been acquired by an orthogonal design of experiment.The density of the emulsion is 0.9 g/cm3,the removal rate of paraffin is 150 g/（mL·min）,and the inhibiting rate of paraffin is 20.70%.When 0.8%～1.5%（mass fraction） sodium chloride is added to the emulsion,the deemulsification time is 1.5～4.0 h.展开更多
基金the supports from Islamic Azad University,Kermanshah Branch
文摘Asphaltene deposition is one of the most seri- ous problems, which usually occurs in oil wells, petroleum production, oil processing, and transportation facilities. Deposition of heavy organic components, especially asphaltene, can lead to wellbore blockage and impacts well economics due to reduction in oil production. Therefore, it is necessary to pay more attention to finding some solution to overcome this problem. In this study, a pipe-loop apparatus for investigation of oil stability was employed to measure deposition thickness using a thermal method. The effects of many factors such as oil type, oil temperature, oil velocity, inhibitors, and solvents on asphaltene deposition were investigated. The results showed that the deposition increased with the increasing value of the colloidal insta- bility index. Besides, the deposition thickness increased with the decreasing velocity of oil, but did not change with oil temperature. In addition, n-heptane could result in more deposition; however, toluene had no effect on the deposi- tion. Branched dodecyl benzene sulfonic acid （Branched DBSA） and Linear DBSA as inhibitors decreased the rate of asphaltene deposition.
基金The authors would like to thank the Research Department of Ahwaz Petroleum University and National Iranian South Oil Company(NISOC)for supporting this study。
文摘One of the most severe problems during production from heavy crude oil reservoirs is the formation of asphaltene precipitation and as a result deposition in the tubing,surface facilities and near wellbore region which causes oil production and permeability reduction in addition to rock wettability alteration in the reservoir.So one of the economical ways to prevent such incidents is using the chemicals which are called asphaltene inhibitor.In this study,the influence of three commercial inhibitors,namely;Cetyl Terimethyl Ammonium Bromide(CTAB),Sodium Dodecyl Sulfate(SDS),Triton X-100 and four non-commercial(Benzene,Benzoic Acid,Salicylic Acid,Naphthalene)inhibitors on two Iranian crude oils were investigated.This study extends previous works and contributes toward the better understanding of interactions between asphaltene and inhibitor.Effect of functional groups and structure of inhibitors on asphaltene precipitation were studied and it seems clear that the nature and polarity of asphaltene(structure and amount of impurities presented)has a significant impact on the selection of inhibitors.asphaltene dispersant tests and Core flood tests were designed for evaluation of inhibitors in static and dynamic conditions.The results revealed distinguished mechanisms for asphaltene solubilization/dispersion(such as hydrogen bonding,pep interaction and acid-base interaction)and influence of additional side group(OH)on inhibition power of inhibitor.During the experiments,it was found that increasing inhibitor concentration may lead to the self-assembly of inhibitor and declining of asphaltene stabilization.So,finding optimum concentration of inhibitor with high efficiency and available at a reasonable price is very important.The results suggest that 600 ppm of CTAB and 300 ppm of SDS were approximately optimum concentrations for the studied crude oils.One of the most important findings that differ from previous studies is the revelation of the mechanism behind the SDS/asphaltene behavior in various concentrations of inhibitor.Effect of chosen inhibitors on asphaltene precipitation and consequently deposition in porous media was studied,and then experimental data were modeled for evaluation of permeability impairment mechanisms.Permeability revived after inhibitor squeezing and cake formation mechanism played an important role in permeability reduction before and after treatment in porous media.The findings can also be applied to prediction of future behavior of reservoirs in oil field scale and evaluation of formation damage in the different period of production if needed any treatment process.
文摘By screening solvents and surfactants,a surfactant with strong wetting and dispersing ability has been discovered,which can form stable emulsions.An O/W emulsifier that can inhibit paraffin deposition and remove it has been acquired by an orthogonal design of experiment.The density of the emulsion is 0.9 g/cm3,the removal rate of paraffin is 150 g/（mL·min）,and the inhibiting rate of paraffin is 20.70%.When 0.8%～1.5%（mass fraction） sodium chloride is added to the emulsion,the deemulsification time is 1.5～4.0 h.
