This paper investigates the macroscopic and microscopic characteristics of viscosity reduction and quality improvement of heavy oil in a supercritical water environment through laboratory experiments and testing.The e...This paper investigates the macroscopic and microscopic characteristics of viscosity reduction and quality improvement of heavy oil in a supercritical water environment through laboratory experiments and testing.The effect of three reaction parameters,i.e.reaction temperature,reaction time and oil-water ratio,is analyzed on the product and their correlation with viscosity.The results show that the flow state of heavy oil is significantly improved with a viscosity reduction of 99.4%in average after the reaction in the supercritical water.Excessively high reaction temperature leads to a higher content of resins and asphaltenes,with significantly increasing production of coke.The optimal temperature ranges in 380–420℃.Prolonged reaction time could continuously increase the yield of light oil,but it will also results in the growth of resins and asphaltenes,with the optimal reaction time of 150 min.Reducing the oil-water ratio helps improve the diffusion environment within the reaction system and reduce the content of resins and asphaltenes,but it will increase the cost of heavy oil treatment.An oil-water ratio of 1︰2 is considered as optimum to balance the quality improvement,viscosity reduction and reaction economics.The correlation of the three reaction parameters relative to the oil sample viscosity is ranked as temperature,time and oil-water ratio.Among the four fractions of heavy oil,the viscosity is dominated by asphaltene content,followed by aromatic content and less affected by resins and saturates contents.展开更多
Tungstated zirconia(WO_(3)/ZrO_(2))solid acid catalysts with different WO_(3) contents were prepared by a hydrothermal method and then used in the catalytic aquathermolysis of heavy oil from Xinjiang.The WO_(3)/ZrO_(2...Tungstated zirconia(WO_(3)/ZrO_(2))solid acid catalysts with different WO_(3) contents were prepared by a hydrothermal method and then used in the catalytic aquathermolysis of heavy oil from Xinjiang.The WO_(3)/ZrO_(2) solid acid catalyst was characterized by a range of characterization methods,including X-ray diffraction,NH3-temperature programmed desorption,and pyridine infrared spectroscopy.The WO_(3) content of the WO_(3)/ZrO_(2) catalysts had an important impact on the structure and property of the catalysts.When the WO_(3) mass fraction was 20%,it facilitated the formation of tetragonal zirconia,thereby enhancing the creation of robust acidic sites.Acidity is considered to have a strong impact on the catalytic performance of the aquathermolysis of heavy oil.When the catalyst containing 20%WO_(3) was used to catalyze the aquathermolysis of heavy oil under conditions of 14.5 MPa,340℃,and 24 h,the viscosity of heavy oil decreased from 47266 to 5398 mPa·s and the viscosity reduction rate reached 88.6%.The physicochemical properties of heavy oil before and after the aquathermolysis were analyzed using a saturates,aromatics,resins,and asphaltenes analysis,gas chromatography,elemental analysis,densimeter etc.After the aquathermolysis,the saturate and aromatic contents significantly increased from 43.3%to 48.35%and 19.47%to 21.88%,respectively,with large reductions in the content of resin and asphaltene from 28.22%to 25.06%and 5.36%to 2.03%,respectively.The sulfur and nitrogen contents,and the density of the oil were significantly decreased.These factors were likely the main reasons for promoting the viscosity reduction of heavy oil during the aquathermolysis over the WO_(3)/ZrO_(2) solid acid catalysts.展开更多
The rheological properties of South China Sea （SCS） crude oil were studied. A group of synthetic long-chain polymers, including octadecyl acrylate-maleic anhydride bidodecyl amide copolymer （VR-D）, octadecyl acryl...The rheological properties of South China Sea （SCS） crude oil were studied. A group of synthetic long-chain polymers, including octadecyl acrylate-maleic anhydride bidodecyl amide copolymer （VR-D）, octadecyl acrylate-maleic anhydride bioctadecyl amide copolymer （VR-O） and octadecyl acrylate-maleic anhydride phenly amide copolymer （VR-A）, were employed to serve as viscosity reducers （VRs）. Their performance was evaluated by both experimental and computational methodologies. The results suggest that the SCS crude oil has low wax content yet high resin and asphaltene contents, which lead to high viscosity through formation of association structures. Additionally, the SCS crude oil appears to be a pseudoplastic fluid showing linear shear stress-shear rate dependence at low temperature. Interestingly, it gradually evolves into a Newtonian fluid with exponential relationship between shear stress and shear rate at higher temperature. Synthetic VRs demonstrate desirable and effective performance on improvement of the rheological properties of SCS crude oil. Upon the introduction of 1000ppm VR-O, which is synthesized by using octadecylamine in the aminolysis reaction, the viscosity of SCS crude oil is decreased by 44.2% at 15 ℃ and 40.2% at 40℃. The computational study suggests significant energy level increase and shear stress decrease for VR-containing crude oil systems.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
Heavy oil is characterized by high viscosity.High viscosity makes it challenging to recover and transport.HZSM-5,MoO_(3)/HZSM-5,ZrO_(2)/HZSM-5 and MoO_(3)–ZrO_(2)/HZSM-5 catalysts were developed to promote in situ de...Heavy oil is characterized by high viscosity.High viscosity makes it challenging to recover and transport.HZSM-5,MoO_(3)/HZSM-5,ZrO_(2)/HZSM-5 and MoO_(3)–ZrO_(2)/HZSM-5 catalysts were developed to promote in situ desulfurization and viscosity reduction of heavy oil.The physical and chemical properties of catalysts were characterized by XPS,XRD,TEM,NH3-TPD,etc.The effects of temperature,catalyst type and addition amount on viscosity and composition of heavy oil were evaluated.The results showed that the presence of MoO_(3)–ZrO_(2)/HZSM-5 nanoparticles during aquathermolysis could improve the oil quality by reducing the heavy fractions.It reduced viscosity by 82.56%after the reaction at 280℃ and catalyst addition of 1 wt%.The contents of resins and asphaltic in the oil samples were 5.69%lower than that in the crude oil.Sulfur content decreased from 1.45%to 1.03%.The concentration of H2S produced by the reaction was 2225 ppm.The contents of sulfur-containing functional groups sulfoxide and sulfone sulfur in the oil samples decreased by 19.92%after the catalytic reaction.The content of stable thiophene sulfur increased by 5.71%.This study provided a basis for understanding the mechanism of heavy oil desulfurization and viscosity reduction.展开更多
Viscosity reduction is an important process in mining heavy oil.To predict the temperature variation and viscosity variation of heavy oil in flow direction,computational fluid dynamics(CFD) was adopted to simulate the...Viscosity reduction is an important process in mining heavy oil.To predict the temperature variation and viscosity variation of heavy oil in flow direction,computational fluid dynamics(CFD) was adopted to simulate the process of heat transfer and flow in this paper.Moreover,an objective function,namely viscosity reduction efficiency,was established to analyze the effect of viscosity reduction.The results indicate that circulating hot water can reduce viscosity significantly,and that the effect of viscosity reduction depends on the inlet temperature and inlet volumetric flow rate of hot water.There is a maximum temperature of heavy oil in flow direction.With the inlet volumetric flow rate of 2.0m3/h and the inlet temperatures of 60,℃,70,℃ and 80,℃,viscosity reduction efficiencies are 94.6%,96.7% and 97.3%,respectively.With the inlet temperature of 70,℃ and the volumetric flow rates of 1.5m3 /h,2.0 m3/h and 2.5m3/h,viscosity reduction efficiencies are 94.4%,96.7% and 97.2%,respectively.展开更多
Fe_(2)O_(3) nanoparticles were first dispersed in a sol solution containing an aluminum component introduced by an initial doping method.Composite catalyst Hierarchical Porous Fe_(2)O_(3)/Al_(2)O_(3) materials(HPFA)we...Fe_(2)O_(3) nanoparticles were first dispersed in a sol solution containing an aluminum component introduced by an initial doping method.Composite catalyst Hierarchical Porous Fe_(2)O_(3)/Al_(2)O_(3) materials(HPFA)were then synthesized through a sol-gel method via phase separation.The performance of HPFA was compared with that of Fe_(2)O_(3) nanoparticle catalysts.The structure of the composite catalyst was characterized by scanning electron microscopy,X-ray diffraction,N_(2) adsorption/desorption,and crush strength testing.The results showed that the Fe_(2)O_(3) nanoparticles could be loaded into the porous skeletons of Hierarchical Porous Al_(2)O_(3) materials(HPA)to achieve a uniform dispersion while avoiding agglomeration,which improved the mechanical strength of the porous materials significantly.The HPFA was then used as a catalyst in the hydrothermal viscosity reduction process of Tuha heavy oil,and the viscosity reduction was investigated.The viscosity reduction rate of HPFA was 81%,which was better than that of the Fe_(2)O_(3) nanoparticles(56%)and HPA(47%).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
Compounding polymer AP-P4 with high viscosity-reducing Gemini Surfactant HD,which is used as an emulsifier viscosity reduce,to improve the stability of the O/W emulsion while the viscosity reduction rate is kept.A pol...Compounding polymer AP-P4 with high viscosity-reducing Gemini Surfactant HD,which is used as an emulsifier viscosity reduce,to improve the stability of the O/W emulsion while the viscosity reduction rate is kept.A polymeric surfactant emulsification and viscosity reduction system capable of forming a relatively stable O/W emulsion of heavy oil(0.5%HD+0.1%AP-P4)is then compounded.The system has been characterized as a high viscosity reduction rate and high stability.Meanwhile,the production liquid does not need to be added with a demulsifier and only needs to be heated to 70°C to achieve effective demulsification.The influencing factors of the performance of the polymetric surfactant emulsification and viscosity reduction system were studied.When the oil-water ratio was 70:30 and 60:40,the viscosity reduction rate was 97.47%and 99.09%,respectively;after 15 h at 30°C,the dehydration rates were 95.8%and 99.2%,respectively.The dehydration rate after 15 h at 70°C was 98.1%and 99.4%,respectively;at 30∼50°C,the water phase temperature has a greater impact on the viscosity;at 60°C,70°C,the water phase temperature has little effect on the viscosity;as the temperature of the aqueous phase increased,the stability of the emulsion deteriorated.When the aqueous phase temperature was 30°C,50°C and 70°C,the dehydration rates of the emulsion after 15 h were 95.8%,96.7%and 98.1%,respectively;As the degree of mineralization increases,the viscosity reduction rate decreases,and the stability of the emulsion deteriorates.The system has been used in field test for 2 injection wells,and the production rate of the two wells increased with a peak value of 25 m3/d and 20 t/d,respectively.展开更多
Due to the high viscosity of heavy crude oils,production from these reservoirs is a demanding task.To tackle this problem,reducing oil viscosity is a promising approach.There are various methods to reduce viscosity of...Due to the high viscosity of heavy crude oils,production from these reservoirs is a demanding task.To tackle this problem,reducing oil viscosity is a promising approach.There are various methods to reduce viscosity of heavy oil:heating,diluting,emulsification,and core annular flow.In this study,dilution approach was employed,using industrial solvents and gas condensate.The viscosity of two Iranian heavy crude oils was measured by mixing with solvents at different temperatures.Dilution of both oil samples with toluene and heptane,resulted in viscosity reduction.However,their effect became less significant at higher concentrations of diluent.Because of forming hydrogen bonds,adding methanol to heavy crude oil resulted in higher viscosity.By adding condensate,viscosity of each sample reduced.Gas condensate had a greater impact on heavier oil;however,at higher temperatures its effect was reduced.Diluting with naphtha decreased heavy oil viscosity in the same way as n-heptane and toluene.Besides experimental investigation,different viscosity models were evaluated for prediction of heavy oil/solvent viscosity.It was recognized that Lederer'model is the best one.展开更多
Oil soluble viscosity reducers have gradually attracted the attention of petrochemical research due to their cleanliness and high efficiency.Considering the high viscosity and non-Newtonian fluid properties of Chenpin...Oil soluble viscosity reducers have gradually attracted the attention of petrochemical research due to their cleanliness and high efficiency.Considering the high viscosity and non-Newtonian fluid properties of Chenping heavy oil found in China,a series of new oil soluble viscosity reducers with different proportions and molecular weights were prepared by free radical polymerization using octadecyl acrylate,2-allylphenol and N-methylolacrylamide as monomers.The viscosity reducer was applied to different types of heavy oil and found that it exhibited a better effect on heavy oils with high asphaltene content.The test of rheological behavior of heavy oil with additive was performed at wide range of shear rate(3–90 s^(-1))and temperature range(30–100°C).The apparent viscosity reduction rate was up to 70.09%,which was better than the industrially relevant ethylene–vinyl acetate copolymer under the same test condition.In addition,the effect of viscosity reducers on the components of heavy oil and the energy change of the system simulated by molecular dynamics simultaneously was investigated.The consistency of the simulated and experimental results show that the effect of viscosity reduction closely related to the crystallization process of wax and the viscosity reducer can reconstruct the surface structure of asphaltene and diminish the connection of benzene ring.展开更多
The apparent shear viscosity （ηα） of a blend composed of 97 wt % high-density polyethylene （HDPE） and 3 wt % polyamide （PA-66） was measured by capillary rheometry at different shear rates, below, near and abov...The apparent shear viscosity （ηα） of a blend composed of 97 wt % high-density polyethylene （HDPE） and 3 wt % polyamide （PA-66） was measured by capillary rheometry at different shear rates, below, near and above the melting point of PA-66, i.e. 240℃, 260℃ and 280℃, respectively. At 260℃ and a high shear rate, ηα of the blend reduced abnormally; and at 260℃, was lower than that at 280℃. The images of etched surface of extrudate observed by the SEM showed different dispersed phase morphology, induced by flow at different temperatures. It is suggested that the formation of fibrillar morphology of dispersed phase is a key factor for the abnormal reduction of ηα for the HDPE/PA blend.展开更多
Two catalysts, nano-sized cobalt-metal-organic framework(Co-MOF) and nickel(Ni)-MOF, were successfully prepared by the modification method. Tetralin(C10H12) was used as the hydrogen donor for the catalytic cracking an...Two catalysts, nano-sized cobalt-metal-organic framework(Co-MOF) and nickel(Ni)-MOF, were successfully prepared by the modification method. Tetralin(C10H12) was used as the hydrogen donor for the catalytic cracking and hydrogenation modification study of the dehydrated crude oil from the Shengli Oilfield. The optimal reaction conditions were determined through orthogonal experiments, and the components of the crude oil and modified oil samples were analyzed. The results revealed that the nanoMOF catalysts were successfully prepared and exhibited high catalytic activity. They could catalyze the cracking of large molecules in heavy oil at mild temperatures(<300°C), leading to the decomposition of the hydrogen donor. When the mass fraction of the catalyst was 0.2%, the mass fraction of the hydrogen donor was 1%, and the reaction temperature was 280°C, the Ni-MOF showed the best catalytic viscosity reduction effect. It could reduce the viscosity of heavy oil at 50°C from 15761.9 m Pa.s to 1266.2 m Pa.s,with a viscosity reduction rate of 91.97%. The modification effect of Co-MOF was the next best, which could reduce the viscosity of heavy oil to 2500.1 m Pa.s with a viscosity reduction rate of 84.14%. Molecular dynamics simulations revealed a strong interaction force between the MOF surface and asphaltene molecules. In the process of heavy-oil catalytic hydrogenation, the nano-MOF catalyst exhibited high catalytic activity. On the one hand, the empty d orbitals outside the metal atoms in the catalyst could polarize the carbon atoms in the organic matter, accelerating the breaking of long chains. On the other hand, the metal atoms in the catalyst could bond with the carbon σ bonds, breaking the carbon-carbon bonds. This disrupted the structure of the recombined components in the crude oil, irreversibly reducing the viscosity of the heavy oil and improving its fluidity.展开更多
The gelation of crude oil with high wax and asphaltene content at low temperatures often results in the block of transportation pipeline in Africa. In recent years, it was reported that surface hydrophobicmodified nan...The gelation of crude oil with high wax and asphaltene content at low temperatures often results in the block of transportation pipeline in Africa. In recent years, it was reported that surface hydrophobicmodified nanoparticles have important applications in crude oil flow modification. In this work, four kinds of core-shell hybride nanoparticles by grafting poly(octadecyl, docosyl acrylate) and poly(acrylate-α-olefin) onto the surface of nano-sized SiO_(2) were synthesized by grafting polymerization method.The chemical structure of nanoparticles was analyzed by Fourier transform infrared spectroscopy(FT-IR),scanning electron microscopy(SEM) and thermogravimetric analysis(TGA). The rheological behaviors of crude oil and precipitation of asphaltenes in the presence of nanoparticles were studied by measuring the viscose-temperature relationship curve, the cumulative wax precipitation amount, and morphology of waxes and asphaltenes. The results indicate that the docosyl polyacrylate@SiO_(2) nanoparticle(PDA@SiO_(2)) can reduce the cumulative wax precipitation amount of crude oil by 72.8%, decline the viscosity of crude oil by 85.6% at 20℃, reduce the average size of wax crystals by 89.7%, and inhibit the agglomeration of asphaltene by 74.8%. Therefore, the nanoparticles not only adjust the crystalline behaviors of waxes, but also inhibit the agglomeration of asphaltenes. Apparently, core-shell hybride nanoparticles provides more heterogeneous nucleation sites for the crystallization of wax molecules,thus inhibiting the formation of three-dimensional network structure. The core-shell polymer@SiO_(2) hybride nanoparticles are one of promising additives for inhibiting crystallization of waxes and agglomeration of asphaltenes in crude oil.展开更多
At present, the main heating method for reducing crude oil viscosity is electric heating, and the all-day electric heating method has the problems of high energy consumption and high cost. In order to meet the needs o...At present, the main heating method for reducing crude oil viscosity is electric heating, and the all-day electric heating method has the problems of high energy consumption and high cost. In order to meet the needs of environmental protection and industrial production, a new type of phase change thermal storage electric heating device was designed by combining the crude oil viscosity reduction heating method with valley price and phase change materials. The results indicate that as the inlet flow rate of the working fluid increases, the outlet temperature continuously decreases. And when the outlet temperature rises to 10?C, the inlet flow rate of the device can meet the flow range of 1.413 - 2.120 m3/h. At the same time, the addition of foam nickel makes the internal temperature of PCM more uniform, and the internal temperature of PCM decreases with the decrease of porosity of foam metal. By increasing the number of electric heating rods and reducing the power of individual electric heating rods, the structure of the device was optimized to significantly improve local high-temperature phenomena. The use of this device can maintain high heat exchange efficiency and reduce production costs.展开更多
Solvents are generally used to reduce the viscosity of heavy crude oil and ultimately enhance oil recovery.Recently,a new method has been introduced where nanoparticles(NPs)are exploited to induce enhanced oil recover...Solvents are generally used to reduce the viscosity of heavy crude oil and ultimately enhance oil recovery.Recently,a new method has been introduced where nanoparticles(NPs)are exploited to induce enhanced oil recovery owing to their ability to improve the mobility ratio,dampen the interfacial tension,and alter rock wett-ability.This study investigated the integration of nano-alumina(Al_(2)O_(3))NPs with an n-hexane solvent.In parti-cular,a Brookfield viscometer has been used to measure the crude oil viscosity and it has been found that NPs can effectively lead to a significant decrease in the overall oil viscosity(70 cp using the solvent only,45 cp when NPs are added).展开更多
This paper presents a new aquathermolysis study of conventional heavy oil in superheated steam. A new high temperature autoclave was designed, where volume and pressure could be adjusted. Aquathermolysis was studied o...This paper presents a new aquathermolysis study of conventional heavy oil in superheated steam. A new high temperature autoclave was designed, where volume and pressure could be adjusted. Aquathermolysis was studied on two different conventional heavy oil samples under different reaction times and temperatures. Experimental results show that aquathermolysis does take place for conventional heavy oil. As reaction time increases, the oil viscosity reduces. However, the reaction will reach equilibrium after a certain period of time and won＇t be sensitive to any further reaction time any more. Analysis shows that, while resin and asphaltenes decrease, saturated hydrocarbons and the H/C ratio increase after reaction. The main mechanism of aquathermolysis includes hydrogenization, desulfuration reaction of resin and asphaltenes, etc.展开更多
Oil-soluble catalysts could be of special significance for reducing the viscosity of heavy crude oil, because of their good dispersion in crude oil and high catalytic efficiency toward aquathermolysis. Ferric oleate w...Oil-soluble catalysts could be of special significance for reducing the viscosity of heavy crude oil, because of their good dispersion in crude oil and high catalytic efficiency toward aquathermolysis. Ferric oleate was synthesized and applied as catalyst in the aquathermolysis reaction of Shengli heavy oil. It was found that ferric oleate was more efficient for heavy oil cracking than Co and Ni oleates. Besides, it was superior to oleic acid and inorganic ferric nitrate and achieved the highest viscosity reduction rate of up to 86.1%. In addition, the changes in the components of Shengli heavy oil before and after aquathermolysis were investigated by elemental analysis, Fourier transform infrared spectrometry, and ^1H nuclear magnetic resonance spectroscopy. Results indicated that ferric oleate contributed to a significant increase in the content of light components and decrease in the content of resin, N and S. The as-prepared ferric oleate showed good activity for reducing the viscosity and improving the quality of the heavy crude oil, showing promising application potential in aquathermolysis of heavy crude oil.展开更多
In order to effectively reduce the viscosity of heavy oil during steam injection, a catalyst system, consisting of reservoir minerals, nickel sulfate, and formic acid, was used to exert catalytic effect on aquathermol...In order to effectively reduce the viscosity of heavy oil during steam injection, a catalyst system, consisting of reservoir minerals, nickel sulfate, and formic acid, was used to exert catalytic effect on aquathermolysis of heavy crude oil extracted from the Liaohe oilfield. Experimental results indicated that all the reservoir minerals used in the experiment had catalytic effect on aquathermolysis and the oil viscosity reduction rate ranged from 24% to 36% after the aquathermolysis reaction. If nickel sulfate was used as the catalyst and added to the reaction system, the oil viscosity reduction rate could reach 50%. If formic acid was used as the hydrogen donor, the oil viscosity reduction rate could increase further, and could reach up to 71.8%. The aquathermolysis reaction of heavy oil under steam injection condition was affected by the reaction temperature, the reaction time, the dosage of minerals, the catalyst concentration, and the hydrogen donor. The experimental results showed that minerals, catalyst and hydrogen donor could work together to enhance aquathermolysis reaction of heavy oil in the presence of the high-temperature water vapor.展开更多
A lipophilic silica/metatitantic acid（denoted as Si O2/H2 TiO 3） nanocomposite was synthesized by hydrothermal reaction with surface-modified Si O2 as the lipophilic carrier. As-synthesized Si O2/H2 TiO 3nanocomposi...A lipophilic silica/metatitantic acid（denoted as Si O2/H2 TiO 3） nanocomposite was synthesized by hydrothermal reaction with surface-modified Si O2 as the lipophilic carrier. As-synthesized Si O2/H2 TiO 3nanocomposite was used as a catalyst to promote the aquathermolysis reaction of extra-heavy crude oil thereby facilitating the recovering from the deep reservoirs at lowered temperature. The catalytic performance of the as-synthesized Si O2/H2 TiO 3catalyst for the aquathermolysis reaction of the heavy oil at a moderate temperature of 150 °C was evaluated in relation to the structural characterizations by TEM,FTIR,XRD and FESEM as well as the determination of the specific surface area by N2adsorption–desorption method. Findings indicate that as-synthesized Si O2/H2 TiO 3nanocomposite exhibits an average size of about 20 nm as well as good lipophilicity and dispersibility in various organic solvents; and it shows good catalytic performance for the aquathermolysis reaction of the extra-heavy oil extracted from Shengli Oilfield of China. Namely,the assynthesized Si O2/H2 TiO 3catalyst is capable of significantly reducing the viscosity of the tested heavy oil from58,000 c P to 16,000 c P（referring to a viscosity reduction rate of 72.41%） at a mass fraction of 0.5%,a reaction temperature of 150 °C and a reaction time of 36 h,showing potential application in downhole upgrading heavy crude oils.展开更多
基金Supported by the Foundation for Innovative Research Groups of National Natural Science Foundation of China(52421002)General Program of National Natural Science Foundation of China(52474016).
文摘This paper investigates the macroscopic and microscopic characteristics of viscosity reduction and quality improvement of heavy oil in a supercritical water environment through laboratory experiments and testing.The effect of three reaction parameters,i.e.reaction temperature,reaction time and oil-water ratio,is analyzed on the product and their correlation with viscosity.The results show that the flow state of heavy oil is significantly improved with a viscosity reduction of 99.4%in average after the reaction in the supercritical water.Excessively high reaction temperature leads to a higher content of resins and asphaltenes,with significantly increasing production of coke.The optimal temperature ranges in 380–420℃.Prolonged reaction time could continuously increase the yield of light oil,but it will also results in the growth of resins and asphaltenes,with the optimal reaction time of 150 min.Reducing the oil-water ratio helps improve the diffusion environment within the reaction system and reduce the content of resins and asphaltenes,but it will increase the cost of heavy oil treatment.An oil-water ratio of 1︰2 is considered as optimum to balance the quality improvement,viscosity reduction and reaction economics.The correlation of the three reaction parameters relative to the oil sample viscosity is ranked as temperature,time and oil-water ratio.Among the four fractions of heavy oil,the viscosity is dominated by asphaltene content,followed by aromatic content and less affected by resins and saturates contents.
基金the financial support from the Open Fund Project of the National Oil Shale Exploitation Research and Development Center,China(No.33550000-22-ZC0613-0255)the Graduate Student Innovation and Practical Ability Training Program of Xi’an Shiyou University(No.YCS23213098)+3 种基金the National Natural Science Foundation of China(No.52274039)the Natural Science Basic Research Plan in Shaanxi Province of China(Program No.2024JC-YBMS-085)the CNPC Innovation Found(No.2022DQ02-0402)The authors also thank the Modern Analysis and Test Center of Xi’an Shiyou University for their help with the characterization of catalysts and analysis of products.
文摘Tungstated zirconia(WO_(3)/ZrO_(2))solid acid catalysts with different WO_(3) contents were prepared by a hydrothermal method and then used in the catalytic aquathermolysis of heavy oil from Xinjiang.The WO_(3)/ZrO_(2) solid acid catalyst was characterized by a range of characterization methods,including X-ray diffraction,NH3-temperature programmed desorption,and pyridine infrared spectroscopy.The WO_(3) content of the WO_(3)/ZrO_(2) catalysts had an important impact on the structure and property of the catalysts.When the WO_(3) mass fraction was 20%,it facilitated the formation of tetragonal zirconia,thereby enhancing the creation of robust acidic sites.Acidity is considered to have a strong impact on the catalytic performance of the aquathermolysis of heavy oil.When the catalyst containing 20%WO_(3) was used to catalyze the aquathermolysis of heavy oil under conditions of 14.5 MPa,340℃,and 24 h,the viscosity of heavy oil decreased from 47266 to 5398 mPa·s and the viscosity reduction rate reached 88.6%.The physicochemical properties of heavy oil before and after the aquathermolysis were analyzed using a saturates,aromatics,resins,and asphaltenes analysis,gas chromatography,elemental analysis,densimeter etc.After the aquathermolysis,the saturate and aromatic contents significantly increased from 43.3%to 48.35%and 19.47%to 21.88%,respectively,with large reductions in the content of resin and asphaltene from 28.22%to 25.06%and 5.36%to 2.03%,respectively.The sulfur and nitrogen contents,and the density of the oil were significantly decreased.These factors were likely the main reasons for promoting the viscosity reduction of heavy oil during the aquathermolysis over the WO_(3)/ZrO_(2) solid acid catalysts.
基金financially supported by the Training Program of the Major Research Plan of the National Natural Science Foundation of China(grant no.91634112)the Natural Science Foundation of Shanghai(grant no.16ZR1408100)+2 种基金the Fundamental Research Funds for the Central Universities of China(grant no.22A201514010)the Open Project of State Key Laboratory of Chemical Engineering(SKL-Ch E-16C01)the institutional funds from the Gene and Linda Voiland School of Chemical Engineering and Bioengineering at Washington State University
文摘The rheological properties of South China Sea （SCS） crude oil were studied. A group of synthetic long-chain polymers, including octadecyl acrylate-maleic anhydride bidodecyl amide copolymer （VR-D）, octadecyl acrylate-maleic anhydride bioctadecyl amide copolymer （VR-O） and octadecyl acrylate-maleic anhydride phenly amide copolymer （VR-A）, were employed to serve as viscosity reducers （VRs）. Their performance was evaluated by both experimental and computational methodologies. The results suggest that the SCS crude oil has low wax content yet high resin and asphaltene contents, which lead to high viscosity through formation of association structures. Additionally, the SCS crude oil appears to be a pseudoplastic fluid showing linear shear stress-shear rate dependence at low temperature. Interestingly, it gradually evolves into a Newtonian fluid with exponential relationship between shear stress and shear rate at higher temperature. Synthetic VRs demonstrate desirable and effective performance on improvement of the rheological properties of SCS crude oil. Upon the introduction of 1000ppm VR-O, which is synthesized by using octadecylamine in the aminolysis reaction, the viscosity of SCS crude oil is decreased by 44.2% at 15 ℃ and 40.2% at 40℃. The computational study suggests significant energy level increase and shear stress decrease for VR-containing crude oil systems.
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.
基金support provided by the National Science and Technology Major Project of the Ministry of Science and Technology of China(2016ZX05012-002-005)Shandong Provincial Natural Science Foundation(Grant no.:ZR2021QE051)+1 种基金National Natural Science Foundation of China(Grant no.:52206291)the Fundamental Research Funds for the Central Universities(Grant no.:22CX06030A).
文摘Heavy oil is characterized by high viscosity.High viscosity makes it challenging to recover and transport.HZSM-5,MoO_(3)/HZSM-5,ZrO_(2)/HZSM-5 and MoO_(3)–ZrO_(2)/HZSM-5 catalysts were developed to promote in situ desulfurization and viscosity reduction of heavy oil.The physical and chemical properties of catalysts were characterized by XPS,XRD,TEM,NH3-TPD,etc.The effects of temperature,catalyst type and addition amount on viscosity and composition of heavy oil were evaluated.The results showed that the presence of MoO_(3)–ZrO_(2)/HZSM-5 nanoparticles during aquathermolysis could improve the oil quality by reducing the heavy fractions.It reduced viscosity by 82.56%after the reaction at 280℃ and catalyst addition of 1 wt%.The contents of resins and asphaltic in the oil samples were 5.69%lower than that in the crude oil.Sulfur content decreased from 1.45%to 1.03%.The concentration of H2S produced by the reaction was 2225 ppm.The contents of sulfur-containing functional groups sulfoxide and sulfone sulfur in the oil samples decreased by 19.92%after the catalytic reaction.The content of stable thiophene sulfur increased by 5.71%.This study provided a basis for understanding the mechanism of heavy oil desulfurization and viscosity reduction.
文摘Viscosity reduction is an important process in mining heavy oil.To predict the temperature variation and viscosity variation of heavy oil in flow direction,computational fluid dynamics(CFD) was adopted to simulate the process of heat transfer and flow in this paper.Moreover,an objective function,namely viscosity reduction efficiency,was established to analyze the effect of viscosity reduction.The results indicate that circulating hot water can reduce viscosity significantly,and that the effect of viscosity reduction depends on the inlet temperature and inlet volumetric flow rate of hot water.There is a maximum temperature of heavy oil in flow direction.With the inlet volumetric flow rate of 2.0m3/h and the inlet temperatures of 60,℃,70,℃ and 80,℃,viscosity reduction efficiencies are 94.6%,96.7% and 97.3%,respectively.With the inlet temperature of 70,℃ and the volumetric flow rates of 1.5m3 /h,2.0 m3/h and 2.5m3/h,viscosity reduction efficiencies are 94.4%,96.7% and 97.2%,respectively.
基金supported by the National Natural Science Foundation of China(51472034)the Cooperation Project of PetroChina Tuha Oilfield Company(2021H10005).
文摘Fe_(2)O_(3) nanoparticles were first dispersed in a sol solution containing an aluminum component introduced by an initial doping method.Composite catalyst Hierarchical Porous Fe_(2)O_(3)/Al_(2)O_(3) materials(HPFA)were then synthesized through a sol-gel method via phase separation.The performance of HPFA was compared with that of Fe_(2)O_(3) nanoparticle catalysts.The structure of the composite catalyst was characterized by scanning electron microscopy,X-ray diffraction,N_(2) adsorption/desorption,and crush strength testing.The results showed that the Fe_(2)O_(3) nanoparticles could be loaded into the porous skeletons of Hierarchical Porous Al_(2)O_(3) materials(HPA)to achieve a uniform dispersion while avoiding agglomeration,which improved the mechanical strength of the porous materials significantly.The HPFA was then used as a catalyst in the hydrothermal viscosity reduction process of Tuha heavy oil,and the viscosity reduction was investigated.The viscosity reduction rate of HPFA was 81%,which was better than that of the Fe_(2)O_(3) nanoparticles(56%)and HPA(47%).
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 authors would like to thank for research funding support of State Key Laboratory of Molecular Engineering of Polymers(Fudan University,Grant No.K2017-25)National Natural Science Foundation of China(Grant No.51674208)+1 种基金Nanchong science and technology planning project(Municipal and university science and technology strategic cooperation special projects,Grant No.NC17SY4017)he Applied Basic Research Programs of Sichuan Science and Technology Plan Project(Grant No.2018JY0515).
文摘Compounding polymer AP-P4 with high viscosity-reducing Gemini Surfactant HD,which is used as an emulsifier viscosity reduce,to improve the stability of the O/W emulsion while the viscosity reduction rate is kept.A polymeric surfactant emulsification and viscosity reduction system capable of forming a relatively stable O/W emulsion of heavy oil(0.5%HD+0.1%AP-P4)is then compounded.The system has been characterized as a high viscosity reduction rate and high stability.Meanwhile,the production liquid does not need to be added with a demulsifier and only needs to be heated to 70°C to achieve effective demulsification.The influencing factors of the performance of the polymetric surfactant emulsification and viscosity reduction system were studied.When the oil-water ratio was 70:30 and 60:40,the viscosity reduction rate was 97.47%and 99.09%,respectively;after 15 h at 30°C,the dehydration rates were 95.8%and 99.2%,respectively.The dehydration rate after 15 h at 70°C was 98.1%and 99.4%,respectively;at 30∼50°C,the water phase temperature has a greater impact on the viscosity;at 60°C,70°C,the water phase temperature has little effect on the viscosity;as the temperature of the aqueous phase increased,the stability of the emulsion deteriorated.When the aqueous phase temperature was 30°C,50°C and 70°C,the dehydration rates of the emulsion after 15 h were 95.8%,96.7%and 98.1%,respectively;As the degree of mineralization increases,the viscosity reduction rate decreases,and the stability of the emulsion deteriorates.The system has been used in field test for 2 injection wells,and the production rate of the two wells increased with a peak value of 25 m3/d and 20 t/d,respectively.
文摘Due to the high viscosity of heavy crude oils,production from these reservoirs is a demanding task.To tackle this problem,reducing oil viscosity is a promising approach.There are various methods to reduce viscosity of heavy oil:heating,diluting,emulsification,and core annular flow.In this study,dilution approach was employed,using industrial solvents and gas condensate.The viscosity of two Iranian heavy crude oils was measured by mixing with solvents at different temperatures.Dilution of both oil samples with toluene and heptane,resulted in viscosity reduction.However,their effect became less significant at higher concentrations of diluent.Because of forming hydrogen bonds,adding methanol to heavy crude oil resulted in higher viscosity.By adding condensate,viscosity of each sample reduced.Gas condensate had a greater impact on heavier oil;however,at higher temperatures its effect was reduced.Diluting with naphtha decreased heavy oil viscosity in the same way as n-heptane and toluene.Besides experimental investigation,different viscosity models were evaluated for prediction of heavy oil/solvent viscosity.It was recognized that Lederer'model is the best one.
基金supported by the National Key Research and Development Program of China(2018YFA0702403)。
文摘Oil soluble viscosity reducers have gradually attracted the attention of petrochemical research due to their cleanliness and high efficiency.Considering the high viscosity and non-Newtonian fluid properties of Chenping heavy oil found in China,a series of new oil soluble viscosity reducers with different proportions and molecular weights were prepared by free radical polymerization using octadecyl acrylate,2-allylphenol and N-methylolacrylamide as monomers.The viscosity reducer was applied to different types of heavy oil and found that it exhibited a better effect on heavy oils with high asphaltene content.The test of rheological behavior of heavy oil with additive was performed at wide range of shear rate(3–90 s^(-1))and temperature range(30–100°C).The apparent viscosity reduction rate was up to 70.09%,which was better than the industrially relevant ethylene–vinyl acetate copolymer under the same test condition.In addition,the effect of viscosity reducers on the components of heavy oil and the energy change of the system simulated by molecular dynamics simultaneously was investigated.The consistency of the simulated and experimental results show that the effect of viscosity reduction closely related to the crystallization process of wax and the viscosity reducer can reconstruct the surface structure of asphaltene and diminish the connection of benzene ring.
文摘The apparent shear viscosity （ηα） of a blend composed of 97 wt % high-density polyethylene （HDPE） and 3 wt % polyamide （PA-66） was measured by capillary rheometry at different shear rates, below, near and above the melting point of PA-66, i.e. 240℃, 260℃ and 280℃, respectively. At 260℃ and a high shear rate, ηα of the blend reduced abnormally; and at 260℃, was lower than that at 280℃. The images of etched surface of extrudate observed by the SEM showed different dispersed phase morphology, induced by flow at different temperatures. It is suggested that the formation of fibrillar morphology of dispersed phase is a key factor for the abnormal reduction of ηα for the HDPE/PA blend.
基金financially supported by the National Natural Science Foundation of China(52174047)Sinopec Project(P21063-3).
文摘Two catalysts, nano-sized cobalt-metal-organic framework(Co-MOF) and nickel(Ni)-MOF, were successfully prepared by the modification method. Tetralin(C10H12) was used as the hydrogen donor for the catalytic cracking and hydrogenation modification study of the dehydrated crude oil from the Shengli Oilfield. The optimal reaction conditions were determined through orthogonal experiments, and the components of the crude oil and modified oil samples were analyzed. The results revealed that the nanoMOF catalysts were successfully prepared and exhibited high catalytic activity. They could catalyze the cracking of large molecules in heavy oil at mild temperatures(<300°C), leading to the decomposition of the hydrogen donor. When the mass fraction of the catalyst was 0.2%, the mass fraction of the hydrogen donor was 1%, and the reaction temperature was 280°C, the Ni-MOF showed the best catalytic viscosity reduction effect. It could reduce the viscosity of heavy oil at 50°C from 15761.9 m Pa.s to 1266.2 m Pa.s,with a viscosity reduction rate of 91.97%. The modification effect of Co-MOF was the next best, which could reduce the viscosity of heavy oil to 2500.1 m Pa.s with a viscosity reduction rate of 84.14%. Molecular dynamics simulations revealed a strong interaction force between the MOF surface and asphaltene molecules. In the process of heavy-oil catalytic hydrogenation, the nano-MOF catalyst exhibited high catalytic activity. On the one hand, the empty d orbitals outside the metal atoms in the catalyst could polarize the carbon atoms in the organic matter, accelerating the breaking of long chains. On the other hand, the metal atoms in the catalyst could bond with the carbon σ bonds, breaking the carbon-carbon bonds. This disrupted the structure of the recombined components in the crude oil, irreversibly reducing the viscosity of the heavy oil and improving its fluidity.
基金Financial support by project of China Petroleum Engineering Corp., Ltd (CPEC), Study on microstructural regulation of polyacrylate and applying as pour-point depressant for crude oil (2021ZYGC-01-01)。
文摘The gelation of crude oil with high wax and asphaltene content at low temperatures often results in the block of transportation pipeline in Africa. In recent years, it was reported that surface hydrophobicmodified nanoparticles have important applications in crude oil flow modification. In this work, four kinds of core-shell hybride nanoparticles by grafting poly(octadecyl, docosyl acrylate) and poly(acrylate-α-olefin) onto the surface of nano-sized SiO_(2) were synthesized by grafting polymerization method.The chemical structure of nanoparticles was analyzed by Fourier transform infrared spectroscopy(FT-IR),scanning electron microscopy(SEM) and thermogravimetric analysis(TGA). The rheological behaviors of crude oil and precipitation of asphaltenes in the presence of nanoparticles were studied by measuring the viscose-temperature relationship curve, the cumulative wax precipitation amount, and morphology of waxes and asphaltenes. The results indicate that the docosyl polyacrylate@SiO_(2) nanoparticle(PDA@SiO_(2)) can reduce the cumulative wax precipitation amount of crude oil by 72.8%, decline the viscosity of crude oil by 85.6% at 20℃, reduce the average size of wax crystals by 89.7%, and inhibit the agglomeration of asphaltene by 74.8%. Therefore, the nanoparticles not only adjust the crystalline behaviors of waxes, but also inhibit the agglomeration of asphaltenes. Apparently, core-shell hybride nanoparticles provides more heterogeneous nucleation sites for the crystallization of wax molecules,thus inhibiting the formation of three-dimensional network structure. The core-shell polymer@SiO_(2) hybride nanoparticles are one of promising additives for inhibiting crystallization of waxes and agglomeration of asphaltenes in crude oil.
文摘At present, the main heating method for reducing crude oil viscosity is electric heating, and the all-day electric heating method has the problems of high energy consumption and high cost. In order to meet the needs of environmental protection and industrial production, a new type of phase change thermal storage electric heating device was designed by combining the crude oil viscosity reduction heating method with valley price and phase change materials. The results indicate that as the inlet flow rate of the working fluid increases, the outlet temperature continuously decreases. And when the outlet temperature rises to 10?C, the inlet flow rate of the device can meet the flow range of 1.413 - 2.120 m3/h. At the same time, the addition of foam nickel makes the internal temperature of PCM more uniform, and the internal temperature of PCM decreases with the decrease of porosity of foam metal. By increasing the number of electric heating rods and reducing the power of individual electric heating rods, the structure of the device was optimized to significantly improve local high-temperature phenomena. The use of this device can maintain high heat exchange efficiency and reduce production costs.
文摘Solvents are generally used to reduce the viscosity of heavy crude oil and ultimately enhance oil recovery.Recently,a new method has been introduced where nanoparticles(NPs)are exploited to induce enhanced oil recovery owing to their ability to improve the mobility ratio,dampen the interfacial tension,and alter rock wett-ability.This study investigated the integration of nano-alumina(Al_(2)O_(3))NPs with an n-hexane solvent.In parti-cular,a Brookfield viscometer has been used to measure the crude oil viscosity and it has been found that NPs can effectively lead to a significant decrease in the overall oil viscosity(70 cp using the solvent only,45 cp when NPs are added).
基金support from the National Natural Science Foundation of China(Grant No.50276040)is gratefully acknowledged.
文摘This paper presents a new aquathermolysis study of conventional heavy oil in superheated steam. A new high temperature autoclave was designed, where volume and pressure could be adjusted. Aquathermolysis was studied on two different conventional heavy oil samples under different reaction times and temperatures. Experimental results show that aquathermolysis does take place for conventional heavy oil. As reaction time increases, the oil viscosity reduces. However, the reaction will reach equilibrium after a certain period of time and won＇t be sensitive to any further reaction time any more. Analysis shows that, while resin and asphaltenes decrease, saturated hydrocarbons and the H/C ratio increase after reaction. The main mechanism of aquathermolysis includes hydrogenization, desulfuration reaction of resin and asphaltenes, etc.
基金the support of the National Natural Science Foundation of China (Nos. 21471047 and 21371047)Natural Science Foundation of Henan Province of China (162300410014)
文摘Oil-soluble catalysts could be of special significance for reducing the viscosity of heavy crude oil, because of their good dispersion in crude oil and high catalytic efficiency toward aquathermolysis. Ferric oleate was synthesized and applied as catalyst in the aquathermolysis reaction of Shengli heavy oil. It was found that ferric oleate was more efficient for heavy oil cracking than Co and Ni oleates. Besides, it was superior to oleic acid and inorganic ferric nitrate and achieved the highest viscosity reduction rate of up to 86.1%. In addition, the changes in the components of Shengli heavy oil before and after aquathermolysis were investigated by elemental analysis, Fourier transform infrared spectrometry, and ^1H nuclear magnetic resonance spectroscopy. Results indicated that ferric oleate contributed to a significant increase in the content of light components and decrease in the content of resin, N and S. The as-prepared ferric oleate showed good activity for reducing the viscosity and improving the quality of the heavy crude oil, showing promising application potential in aquathermolysis of heavy crude oil.
基金the financial supports from National Key Project of Scientific and Technical Supporting Programs:Enhancing oil displacement efficiency during steamfloods(fund No.2008ZX05012-001)
文摘In order to effectively reduce the viscosity of heavy oil during steam injection, a catalyst system, consisting of reservoir minerals, nickel sulfate, and formic acid, was used to exert catalytic effect on aquathermolysis of heavy crude oil extracted from the Liaohe oilfield. Experimental results indicated that all the reservoir minerals used in the experiment had catalytic effect on aquathermolysis and the oil viscosity reduction rate ranged from 24% to 36% after the aquathermolysis reaction. If nickel sulfate was used as the catalyst and added to the reaction system, the oil viscosity reduction rate could reach 50%. If formic acid was used as the hydrogen donor, the oil viscosity reduction rate could increase further, and could reach up to 71.8%. The aquathermolysis reaction of heavy oil under steam injection condition was affected by the reaction temperature, the reaction time, the dosage of minerals, the catalyst concentration, and the hydrogen donor. The experimental results showed that minerals, catalyst and hydrogen donor could work together to enhance aquathermolysis reaction of heavy oil in the presence of the high-temperature water vapor.
基金supported by the National Natural Science Foundation of China (grant Nos.21371047 and 21471047)
文摘A lipophilic silica/metatitantic acid（denoted as Si O2/H2 TiO 3） nanocomposite was synthesized by hydrothermal reaction with surface-modified Si O2 as the lipophilic carrier. As-synthesized Si O2/H2 TiO 3nanocomposite was used as a catalyst to promote the aquathermolysis reaction of extra-heavy crude oil thereby facilitating the recovering from the deep reservoirs at lowered temperature. The catalytic performance of the as-synthesized Si O2/H2 TiO 3catalyst for the aquathermolysis reaction of the heavy oil at a moderate temperature of 150 °C was evaluated in relation to the structural characterizations by TEM,FTIR,XRD and FESEM as well as the determination of the specific surface area by N2adsorption–desorption method. Findings indicate that as-synthesized Si O2/H2 TiO 3nanocomposite exhibits an average size of about 20 nm as well as good lipophilicity and dispersibility in various organic solvents; and it shows good catalytic performance for the aquathermolysis reaction of the extra-heavy oil extracted from Shengli Oilfield of China. Namely,the assynthesized Si O2/H2 TiO 3catalyst is capable of significantly reducing the viscosity of the tested heavy oil from58,000 c P to 16,000 c P（referring to a viscosity reduction rate of 72.41%） at a mass fraction of 0.5%,a reaction temperature of 150 °C and a reaction time of 36 h,showing potential application in downhole upgrading heavy crude oils.
