Asphalt Content Research Articles

Cyclopentane hydrate wettability measurements used to evaluate the efficacy of oil natural surfactants using ultra-low volume samples

Hydrate surface wettability is a fundamental aspect to better understand agglomeration present in oil bearing petroleum pipelines. Coupling these measurements with hydrate film growth gives further information on kinetic effects that may also be present from natural surfactants in different oils. In situ measurements of wettability (quantified by the contact angle) and film growth rates were performed on cyclopentane hydrate surfaces at atmospheric pressure and subcooling of 4 °C. Contact angle and film growth results were obtained for the baseline system (pure cyclopentane), one model oil, and seventeen natural oils (diluted to 0.02 vol% in cyclopentane). Results showed a wide variety of contact angles and film growth values where higher asphaltene contents in the oils corresponded to higher contact angles and lower film growth rates, thought to be from better alignment of natural surfactant molecules at the hydrate/hydrocarbon interface. It was also shown for select oils that increasing the oil concentration in the cyclopentane increases the contact angle and decreases the film growth rate compared to the baseline system. For select oils that had higher contact angles, increasing the water content of the system decreases their contact angle and film growth compared to the baseline system. Isolating different oil fractions for select oils also shows which fractions tend to play a larger role in wettability behavior. Typically, the fractions with more surface active components (asphaltene and resins) are shown to contribute to the higher contact angle and slower film growth rates for select oils. Evidence of the competition between film growth and capillary suction of water into the hydrate has been shown, and a mechanistic breakdown of three different transient scenarios has been proposed. Each of these observed interfacial behaviors gives information on what can be expected from larger scale phenomena, including hydrate agglomeration, with very small oil samples.

Porous Asphalt Mixture with Improved Fatigue Resistance and Stormwater Pollutant Reduction in Urban Road Pavement

One alternative measure to minimise the stormwater runoff volume and its pollutants and reduce impervious areas is to use permeable pavement. However, due to weak mechanical performance under heavy-load traffic related to fatigue resistance, porous mixtures and permeable pavements have restricted applications, i.e., parking lots and low-traffic roads. This work aims to evaluate the fatigue resistance of a porous asphalt mixture produced with highly modified asphalt (HiMA) and its potential contribution to reducing stormwater runoff and pollutants. In order to estimate the capability of runoff pollutants and stormwater flood reduction, a case study was performed on an urban road. A permeable pavement was designed using the porous mixture as a surface layer. The mixture volumetric parameters and asphalt content were established using the Marshall method, considering the void content, interconnected voids, permeability, Cantabro test, and moisture damage test evaluation. The resilient modulus and fatigue resistance tests were performed on a diametral compression device. The mixture design resulted in an asphalt content of 5.1% and a void content of 21.5%. The resilient modulus was 2764 MPa, and the porous mixture obtained excellent fatigue performance, allowing its application in diverse traffic conditions. The porous mixture efficiency infiltration capacity was 90%, and some runoff pollutants could be reduced after being filtered by the pavement surface, contributing to minimizing environmental contamination. This work filled part of a gap in predicting porous mixtures’ fatigue performance, collaborating to popularise and expand its use for various purposes.

Influence of Oyster Shell Ash Filler on the Marshall Properties of Asphalt Concrete

Roads are vital for the movement of people and goods, and their durability and mechanical properties depend on various factors, including the construction materials used. Marshall properties are crucial for analysis of asphaltic concrete designed for road construction, Also, filler materials improves the properties of asphaltic concrete. Therefore, this study investigated the influence of oyster shell ash (OSA) on the Marshall properties of hot mix asphalt concrete. The Marshall properties analyzed include stability, flow, void in mineral aggregate (VMA), void in the mixture (VIM), void filled with asphalt (VFA), and Marshall Quotient (MQ). The research revealed that the addition of oyster shell ash enhanced the stability and flow of asphaltic concrete. VMA and VFA increased with increase in OSA content, while increase in asphalt content resulted in a decrease in VIM and increase in VFA. The optimum performance of the Marshall’s properties was recorded at 10% OSA and 5% asphalt content. The study also showed that the OSA-filled asphaltic concrete improved the performance of the OSA-filled asphalt concrete stability and stiffness compared to the sample without OSA. Moreover, OSA enhances the stiffness of the mixture, as reflected by the Marshall Quotient. Therefore, the findings highlighted the potential of oyster shell ash as a viable and sustainable filler material in asphaltic concrete.

A Guide for Selection of Aging Time and Temperature for Wettability Alteration in Various Rock-Oil Systems.

Wettability alteration has been identified to be one of the important mechanisms to improve the microscopic recovery in many of the enhanced oil recovery (EOR) methods including polymer flood, surfactant flood, low salinity flood, microbial flood, alkaline flood, etc. Ensuring the oil-wet nature of the formation before flooding in the laboratory is necessary to study the efficiency of the EOR process, which targets microscopic recovery through wettability alteration. Nevertheless, altering the wettability depends on several parameters, such as aging time, aging temperature, core nature, oil properties, etc. Although several researchers investigated the effect of individual parameters on wettability alteration, the literature is scarce, and the question of what is the shortest and yet the most reliable aging time for ensuring wettability alteration for the specific rock-oil system at different temperatures remains unclear. This paper attempts to seek an answer to this question by compiling the relevant literature to find the effect of individual parameters such as different aging times, temperatures, oil compositions, and rock lithologies on wettability alteration. Results observed from data analysis showed different windows for aging conditions depending on the core sample lithology, initial wettability, and type of oil used. It was noticed that the higher the asphaltene content in the crude oil used, the lower the time and temperature that it takes to alter the sample wettability. Aging a sandstone core under 80 °C using crude oil with 11 wt % % asphaltene took 7 days to shift the core from strongly water-wet to neutral-wet. The same wettability alteration was achieved in 14 days when aging the sandstone sample at 90 °C using crude oil with 0.85 wt % asphaltene content. Generally, it was observed that the aging time decreased as the temperature increased. Moreover, as the sample has a lower initial water wettability condition, the time that it needs to be aged becomes higher. Results indicated that carbonates in general require less aging time to alter their wettability condition to oil-wet, around 1-7 days, compared with sandstones, around 14-21 days.

Migration mechanism of pyrolysis oil during oil shale in situ pyrolysis exploitation

In situ pyrolysis exploitation is an ideal method for the utilization of oil shale. The migration of pyrolysis oil has significant effects on the in situ exploitation process, such as reservoir permeability and oil quality; it further determines the feasibility and economy of this technology. However, the migration mechanism of pyrolysis oil components in the reservoir after hydraulic fracturing has not been fully revealed, so the exploitation process still lacks comprehensive theoretical guidance. In this study, visual experiments of pyrolysis oil migration were carried out, and simulations were also performed based on the adjusted reaction model including the behaviors of asphaltene. Experiment and simulation results collectively indicated that the separation of oil components was evident in the reservoir with a higher temperature, and the alternate cycle of volatilization-migration-condensation was the primary migration pattern of pyrolysis oil. Due to asphaltene deposition and high-viscosity oil accumulation, reservoir permeability was significantly reduced in the middle stage of exploitation. In addition, the asphaltene content in the produced oil decreased to ∼2.8%, the produced oil quality and energy conversion ratio improved markedly when the temperature of injected nitrogen was 500 °C. Results obtained could guide the oil shale in situ pyrolysis exploitation.

The Catalytic Upgrading Performance of NiSO4 and FeSO4 in the Case of Ashal’cha Heavy Oil Reservoir

Aquathermolysis is a promising process for improving the quality of heavy oil under reservoir conditions. However, the application of catalysts during the process can significantly promote the transformation of the heavy fragments and heteroatom-containing compounds of crude oil mixtures into low-molecular-weight hydrocarbons. This research paper conducted a comparative analysis of the catalytic effectiveness of water-soluble metal salts like NiSO4 and FeSO4 in the process of aquathermolysis to upgrade heavy oil samples extracted from the Ashal’cha reservoir. The temperature of the experiment was 300 °C for a duration of 24 h. Compared to the viscosity of the native crude oil, the Fe nanoparticles contributed to a 60% reduction in viscosity. The viscosity alteration is explained by the chemical changes observed in the composition of heavy oil after catalytic (FeSO4) aquathermolysis, where the asphaltene and resin contents were altered by 7% and 17%, accordingly. Moreover, the observed aquathermolytic upgrading of heavy oil in the presence of FeSO4 led to an increase in the yield of gasoline fraction by 13% and diesel fraction by 53%. The H/C ratio, which represents the hydrogenation of crude oil, increased from 1.52 (before catalytic upgrading) to 1.99 (after catalytic upgrading). The results of Chromatomass (GC MS) and Fourier-transform infrared spectroscopy (FT-IR) show the intensification of destructive hydrogenation reactions in the presence of water-soluble catalysts. According to the XRD and SEM-EDX results, the metal salts are thermally decomposed during the aquathermolysis process into the oxides of corresponding metals and are particularly sulfided by the sulfur-containing aquathermolysis products.

A comparison study of using polyethylene terephthalate and limestone fillers on porous asphalt mixture behaviours

Regardless of their gradations, all varieties of asphalts pavement mixtures are smooth and impermeable, which reduces the safety of cars in different weather situations. Comfort and safety on the roads during various weather conditions are directly influenced by surface layer characteristics. Porous asphalt has quick surface drainage, eliminates splashing, and improves safety. Additionally, because water drains into the asphalt mixture's pores, the desired level of friction between the tire and the pavement will be guaranteed. This necessitates the production of permeable asphalt pavement mixtures for roads and highways that can handle heavy traffic loads. The primary objective of this study is to investigate the enhancement of stability and mechanical properties in porous mixtures by substituting conventional limestone filler with Polyethylene Terephthalate Waste Plastic (PET) powder. Simultaneously, the study aims to mitigate environmental pollution by utilizing PET materials, which take decades to decompose naturally. The PET used in the study was melted at 260 0C and then powdered using 7000, 18000, and 28000 rpm grinders to obtain filler that passed sieve no. 200. The ASTM D7064-based evaluation of the mixture's optimum asphalt content takes into account essential factors, including drain down, percentage of air voids, and optionally, the results of the Cantabro abrasion test, which was calculated to be 4.75%, decreased to 4.5% when polyethylene terephthalate powder was utilized as filler in place of limestone. The optimum limestone filler percentage was 3.0% based on National Asphalt Pavement Association (NAPA) gradation employed the same procedure in the optimum asphalt content evaluation. However, the results showed that the optimum amount when using PET powder reached 3.5%.The criteria used to investigate the newly proposed asphalt pavement mixture are the Marshall method, Drain down of binder, Cantabro loss test, and permeability of porous mixture. This research reveals that adding PET as an alternative filler to limestone reduces permeability, Drain Down, and Cantabro by 22.64%, 29.27%, and 16.33% respectively while increasing the stability by more than 15.5%. It is still promising that the permeability of the mixture stays within the desirable limit for comfort and safe driving. Filler replacement was tied to performance testing and was demonstrated to raise the deformation strength in the KIM test more than twice from 1.54 MPa to 3.63 MPa by employing a specialized head and Marshall loading machine as an alternative method to the wheel tracking test for evaluating rutting in the mixture. The index of retained stability by aging the samples in water bath at 25 °C from one to four days increased from 8.66 MPa by 33.1% to reach 12.57 MPa where filler replaced, and the indirect tensile strength based on ASTM D4867raised by 29.08% from 0.578 to 0.735 MPa for conditions samples and raised from 0.681 to 0.879 MPa to raise the unconditioned samples by 12.9%. It is also worth noting that the use of PET as a waste material has significant environmental benefits.

Impacts of Ignition Furnace Correction Factor Errors on Quality Assurance of Asphalt Mixtures

The accurate determination of asphalt content has long been a key component of assessing the quality and characteristics of an asphalt mixture, with the ignition method (AASHTO T 308) being the most common. Despite previous research work recommending the use of unique correction factors for each mixture and oven, the practice of sharing correction factors is very prevalent. A unique dataset of correction factors and ignition furnace results generated by Maine Department of Transportation (MaineDOT) is analyzed to quantify the potential errors in a production environment induced by the practice of sharing correction factors and apply those errors to different quality assurance systems. The work is based largely on correction factors generated by MaineDOT for the same design in multiple ovens across two laboratories. The difference in mixture type was evident in the correction factor data and the difference in correction factors in the same design ranged from 0.0% to 0.43%, with most differences between 0.07% and 0.15%. Larger differences in correction factors were observed between different laboratories then when they were generated for different furnaces in the same laboratory. Analysis of acceptance data and percent-within-limits simulations showed that sharing of correction factors, even in cases when the differences are small, resulted in significant impacts on quality acceptance and payment. The added variability can result in errors in assessment of quality, errors in payment to the producer, unnecessary corrective action by the producer, and a more variable finished product. Agencies and producers using AASHTO T 308 are encouraged to evaluate the differences in correction factors between their furnaces and laboratories to quantify the impact of errors on their quality assurance programs for asphalt mixtures.

Cold recycling mix design approach targeting permanent deformation resistance

Cold recycling technology offers a sustainable construction pathway for pavements with a potential of recycling up to 100% of the existing in-situ materials. This study introduces a new approach to design emulsion-based cold recycling mixtures. The proposed mix design approach channels the design efforts to optimize the mixture’s components and evaluate its long-term performance. The elements of the proposed design include altering aggregate gradation to achieve optimum packing; a method to selecting an optimum moisture content that is derived from both liquid components in the mixture; and selecting the residual asphalt content based on the mixture’s resistance to permanent deformation. To evaluate the reliability of the proposed mix design method, an optimum mixing water content was derived for an optimum RAP gradation. The effect of varying the emulsion content while keeping the mixing water content constant was evaluated on the mixture’s volumetrics, strength, and permanent deformation behavior. A conventional triaxial compression stress path was applied on samples compacted with several residual asphalt contents. The triaxial test results were compared with results obtained from Hamburg Wheel Tracking Test and Asphalt Pavement Analyzer rutting device. The increase in residual asphalt content at optimum mixing water content led to a systematic increase in strength and reduction in voids that stabilizes as the content increases. The permanent deformation experiments showed the importance of imposing a deformation criterion to select the residual asphalt content in the mix design stage. Additionally, the triaxial repeated load tests demonstrated the importance of using anticipated stress states to characterize permanent deformation resistance which cannot be captured by simple performance tests. Representative stress states in the CR layer should be taken into account during the mix design stage where higher stresses are anticipated in the recycled layer.

Research on the effects of asphalt performance on rutting resistance and its correlation with rutting performance indicators

The rutting development of asphalt pavement is generally divided into two stages including the initial densification and the shear slow. The rutting resistance of asphalt mixture is greatly affected by the performance of asphalt. However, the effects of asphalt performance on the different rutting development stages are not fully clear. This paper is aimed to evaluate the applicability of rutting performance indicators to asphalt performance and further identify the correlation of changes in asphalt performance with rutting development stages. The rutting tests were carried out to study the effect of asphalt performance on the rutting resistance, in which the asphalt grade, modifier type and content, and asphalt type were involved. The dynamic stability (DS), complex stability index (CSI), Tseng-Lytton (A/C), and Gladkikh (1/E) models were selected as the rutting performance indicators. Results of the rutting test show that the application of low-grade asphalt and modifier has a larger reduction in the rutting depth. The polyethylene (PE) modifier has the largest contribution to the rutting resistance and a better composite modified effect with the styrene–butadiene–styrene (SBS) modified and 30# asphalt. The asphalt mixtures with low-grade and crumb rubber (CR) modified asphalt have the lowest temperature sensitivity. Furthermore, the asphalt performance has great effects on the initial densification stage, as well as the shear slow stage. The A/C and CSI that are related to both the initial and secondary rutting stages are the most reliable indicators to characterize the effect of asphalt performance on the rutting resistance of asphalt mixture. The correlations of DS and 1/E with the rutting depth are lower than the former two indicators, indicating that these only related to the secondary rutting stage are not recommended.

Estimating permeability impairment due to asphaltene deposition during the natural oil depletion process using machine learning techniques

Asphaltene deposition causes numerous problems in the petroleum industry, including porous media blockage. To better understand the effect of rock and oil properties, as well as operational parameters, on reservoir permeability reduction due to asphaltene deposition during the natural depletion of oil, this study explored the capability of ensemble learning models, including Extra Trees, Gradient Boosting, Adaboost, XGBoost, LightGBM, and Random Forest, for estimating permeability decline. A set of potential parameters affecting permeability impairment were identified to develop the model, and a dataset of 1189 samples was created and divided into training and testing categories in a 4:1 ratio. The Optuna optimization framework was used to estimate the models hyperparameters. Our findings indicate that eight parameters, including pore volume injected, API, asphaltene content, porosity, injection velocity, permeability, core area, and lithology, are the most important predictors for estimating permeability reduction. Evaluation results using testing data (238 samples) demonstrated that the developed models accurately predicted permeability reduction, of which the Extra Trees method outperformed the others, with Root Mean Square Error (RMSE) and coefficient of determination (R2) values of 0.03 and 0.98, respectively. These findings have implications for the petroleum industry and offer a more affordable and efficient alternative to laboratory studies for evaluating formation damage caused by asphaltene deposition.

Rapid accuracy determining DNA purity and concentration in heavy oils by spectrophotometry methods

DNA analysis is the core of biotechnology applied in petroleum resources and engineering. Traditionally accurate determination of DNA purity and concentration by spectrometer is the first and critical step for downstream molecular biology research. In this study, three different spectrophotometry methods, BPM, NDTT and NPMTTZ were compared for their performance in determining DNA concentration and purity in 32 oil samples, and molecule methods like quantitative real-time PCR (qPCR) and high-throughput sequence were also performed to help assess the accuracy of the three methods in determining DNA concentration and purity. For ordinary heavy oil (OHO), extra heavy oil (EHO) and super heavy oil (SHO), the characteristics of high viscosity (η), density (ρ) and resin plus asphaltene content will affect the DNA extraction and UV determination. The DNA concentration was decreased as density increased: OHO (11.46 ± 18.34 ng/μL), EHO (6.68 ± 9.67 ng/μL) and SHO (6.20 ± 7.83 ng/μL), and the DNA purity was on the reverse: OHO (1.31 ± 0.27), EHO (1.54 ± 0.20), and SHO (1.83 ± 0.32). The results suggest that spectrophotometry such as BPM and NPMTTZ are qualitatively favorite methods as the quick non-consumable methods in determining DNA concentration and purity of medium oil and heavy oil.

Asphalt concrete mix analysis using volcanic ash filler

Asphalt mixture is a combination of a mixture of aggregate and asphalt. Sinabung eruption volcanic ash produced many negative impact on health and the environment. So that needs to be done in order to study the volcanic ash can be used in road pavement, especially on Asphalt Concrete pavement, the purpose of this study to determine the effect comparison of volcanic ash filler sinabung on Asphalt Concrete - Binder Course. This research was laboratory experimental in nature with asphalt level variation of 5%, 5.5%, 6%, 6.5%, 7% and volcanic filler level of 1, 2 and 3% in each asphalt level variation. There were 5 samples used the examination was done using marshall test instrument. The test used to determine the graph of asphalt content with value stability, flow, bulk density, VIM, VMA, VFB. The results of the over all addition of volcanic ash in the petroleum asphalt. Asphalt Concrete Binder Course Marshall stability values indicate that the better that showed that a mixture of aggregate is very good. If the flow value is lower, the VIM value is getting lower, then the VMA value and VFB value have a value that is more than the minimum value.

Effect of sodium hydroxide, sodium dodecyl benzenesulfonate, and resin on the interfacial tension of asphaltenic synthetic oil extracted from acidic crude oil under low salinity condition

During the past years, the usage of new oil recovery methods known as enhanced oil recovery methods is increasing because of energy consumption rate enhancement and reservoir pressure depletion. Unfortunately, since most of the investigations were focused on crude oil, it is hard to find a generalized pattern of interfacial tension (IFT) and wettability change for different crude oils because of its complicated composition. So, it is necessary to examine the effect of specific fractions of crude oil especially resin and asphaltene fractions on the IFT and wettability alteration using systematic investigations. Although a limited number of investigations examined the interactions between these specific fractions and salts, there are no systematic reports respecting the possible interactions between asphaltene and resin fractions in the presence of alkaline and surfactant. So, in the first stage, the impact of dissolving asphaltene (0–9 wt%) in the toluene was investigated on the IFT reduction which revealed a decrease in IFT value from 34.8 to 23.3 mN/m as the asphaltene concentration was increased. Further experiments showed that the presence of MgCl2 and NaCl with a maximum concentration of 5000 ppm led to a reduction in IFT to a minimum value of 18.3 and 17.3 mN/m for NaCl and MgCl2, respectively, which means the higher impact of MgCl2 on the IFT reduction. After that, the selected optimum concentrations of MgCl2 and NaCl (5000 ppm) were used in the rest of the experiments in which the effect of resin fraction and other chemicals including sodium dodecyl benzenesulfonate (SDBS) and NaOH concentrations was examined on the IFT reduction and rock wettability. According to the obtained results, it was possible to reach the minimum IFT value of 0.08 mN/m, which is several orders lower than the original IFT value of the binary system without the chemicals using the optimum chemical formulation obtained by mixing proper concentrations of SDBS, NaOH, MgCl2, and NaCl. Moreover, the obtained optimum formulations were used through core flooding experiments which revealed the possibility of increasing the oil recovery to a maximum value of 10.1% based on the original oil in place.

Investigating the role of asphaltenes structure on their aggregation and adsorption/deposition behavior

Despite the existing literature, the mechanisms of asphaltenes aggregation, precipitation, and adsorption/deposition in relation to the structural motifs of asphaltenes remains unclear. In this study, the aggregation and adsorption/deposition of asphaltenes extracted from light, medium, and heavy oils, as well as three distinct subfractions of the medium oil asphaltenes were investigated. The role of asphaltenes structure, concentration, sonication time, and precipitant addition on asphaltenes aggregation was investigated. The adsorption/deposition behavior of asphaltenes on gold surface revealed similar dependency on asphaltenes structure as their aggregation kinetics. The measured adsorption/deposition mass of the studied asphaltenes on a gold surface ranged from 590 to 5600 ng/cm2. Light and medium oil asphaltenes, as well as the least soluble subfraction underwent self-association in toluene, whereas self-association was less evident for heavy oil asphaltenes or the most soluble subfraction. Shorter sonication time, increased concentration and n-heptane addition accelerated asphaltenes aggregation, as expected. Diffusion-limited aggregation followed by reaction-limited aggregation kinetics were identified upon n-heptane addition. The more soluble subfractions were found to assist in stabilizing the parent asphaltenes and the less soluble subfractions.

Modified asphalt-rubber green pavement (MARGPave) mixtures: Product development and performance assessment

The major objective of this study was to develop “Modified Asphalt-Rubber Green Pavement (MARGPave)” mixtures with dense- and gap-graded aggregate structures to accomplish performance attributes superior to the conventional asphalt-rubber mixtures. The scope encompassed production of one conventional dense-graded, one dense-graded MARGPave, one gap-graded MARGPave, and one gap-graded asphalt-rubber mixtures using the Superpave mix design, conduct of stiffness modulus tests, moisture sensitivity, and fatigue evaluation at varying temperature-frequency combinations, which generated over 300 data points. The dense-graded MARGPave mix exhibited three times higher fatigue life and increased durability than the conventional dense-graded mix. The gap-graded MARGPave mix had lower modulus at all temperatures by more than 50% than the dense-graded MARGPave mix due to 2% higher asphalt content and rubber inclusions. Likewise, the modulus of gap-graded MARGPave mix was higher than gap-graded asphalt-rubber mix across all temperatures and frequencies, indicative of the elastic nature of the MARGPave mix due to higher rubber content. Higher modulus at higher temperatures and lower modulus at lower temperatures were concurrently displayed by dense-graded MARGPave mix, which indicated that the material would be resistant against rutting and low-temperature thermal cracking, thereby able to outperform conventional materials with insignificant rate of change of viscosity with increasing temperatures, and the presence of rubber particles that would render the mix the necessary additional resilience to endure the mix performance for the entire design life. It is noteworthy that the procedure of blending asphalt binder, aggregates, and the modified asphalt-rubber product that replaces some portions of fine aggregates helped create MARGPave mixtures that was found akin to the semi-dry process technology. It is envisioned that the indigenously developed MARGPave mixtures will be best suited as a roadway construction and maintenance strategy that supports the engineering use of end-of-life tires, encouraging the waste-to-wealth concept.

Analysis of the Contribution of Petroleum Acid Components to the Viscosity of Heavy Oils with High TAN.

The viscosity of heavy oil hinders its cold production, posing a major challenge to its exploitation. The high viscosity of heavy oil can be attributed to the content of asphaltene. However, during the collection of heavy oil samples from various regions in China, we observed that heavy oils with high total acid number (TAN) but low asphaltene content also exhibit relatively high viscosity. Hence, the viscosity mechanism of high-acid crude oil, the influence of petroleum acid on heavy oil viscosity, should be investigated. In this study, Xinjiang Chunfeng heavy oil was selected for analysis, possessing a viscosity of 16,886 mPa·s at 50 °C and a high total acid number (TAN) of 17.72 mg KOH/g. Separation was performed on the deacidified oil and the acid component using an alkali-modified silica gel column. The viscosity changes of the deacidified oil and its blends with varying proportions of the acid component were determined, along with the viscosity changes of the deacidified oil and acid components in a toluene solution. The molecular composition was analyzed using a Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS). The findings indicated successful separation of petroleum acid from the heavy oil, the acid component yield being 16.65 wt %. Furthermore, the viscosity of the petroleum acid was significantly higher than that of the deacidified oil. The rate of viscosity change of the acid component in the toluene solvent exceeded that of the deacidified oil, and the viscosity of the deacidified oil notably increased upon the addition of acid. In conjunction with the viscosity data, it was observed that the deacidified oil exhibited the removal of O2 and O4 compounds, resulting in a 43.11% viscosity reduction at 30 °C compared with crude oil. Thus, the monoacid and diacid components considerably affected the viscosity of heavy oil.

Factors and Kinetics Related to the Formation of Heavy Oil-in-Water Emulsions

Oil-in-water emulsions provide an essential contribution to enhanced oil recovery by acting as oil displacement and conformance control systems. However, the dominant factors affecting their emulsification and kinetics are unclear. The emulsification rate is usually defined in terms of changes in the torque, conductivity, or particle size over time, which results in inaccurately calculated emulsified oil amounts. Therefore, the effects of temperature, pH, and NaCl concentration on the emulsified mass and droplet sizes of aqueous emulsions of Jin8-7 and Chen373 oil with octadecyl amine ethoxylate ether as an emulsifier were investigated. The results showed that the formation of oil-in-water emulsions of Jin8-7 and Chen373 under different conditions occurred via a two-stage mechanism: rapid emulsification and emulsion maturation. The emulsified oil mass rapidly increased during the rapid emulsification period and plateaued during the emulsion maturation period. This indicates that the emulsified oil mass largely depended on the short rapid emulsification period. It was also found that increasing the temperature and pH were more conducive to the emulsification of Chen373 oil with a high viscosity and high asphaltene content. The optimal NaCl concentration was determined to be 2% and 4% for Chen373 and Jin8-7 oil, respectively, based on the emulsification mass during the rapid emulsification period. The droplet size decreased first and then increased during the emulsification process under most experimental conditions. A second-order kinetics model for emulsification was proposed, in which the evolution of emulsified oil mass calculated with time agreed with the experimentally measured values. This study can provide theoretical guidance for the implementation of chemical cold production of heavy oil in oilfields.

Study on influencing factors and distribution probability of asphalt mixtures’ rutting samples physical indices

Rutting deformation is one of the most prominent diseases in asphalt pavement’s early damage. In this study, the main influencing factors, mechanism, and distribution law of the principal physical indices of AC-13 asphalt mixture rutting specimens were analyzed based upon the rutting test and statistical principles. Firstly, the main influencing factors, mechanism, and changes law of AC-13 asphalt mixture rutting specimens’ main physical indices were analyzed, based upon a large number rutting test results. Secondly, it analyzes the optimum fitting distribution of the main indices based upon statistical principles. The results showed that, as the asphalt content increased, the mixture rutting samples’ ρf and VMA indices increased firstly and then decreased, VV increased and VFA changed in the converse direction. There was a good linear correlation between the indices Sa and Vbe and asphalt content, in which the indices showed an opposite change trend. The content of coarse aggregate increased by 5.5% in the asphalt mixture, the rutting samples’ ρf increased by 2.03%, and the indices VV, VMA, VFA, Sa, and Vbe decreased by 35.23, 9.1, 8.86, 35.79, and 7.60% on average, respectively. The Marshall testing specimens’ ρf, VV, and VMA were similar to those that were wheel rolled 18 times, and VFA was similar when rolled 12 times. As the number of times the mixtures were rolled increased by 6, the asphalt mixtures’ ρf, VFA, and Vbe increased by 2.05, 8.47, and 1.44%, while the indices VV, VMA, and Sa decreased by 29.49, 8.81, and 11.55%, respectively. The optimal distribution fitting function of the asphalt mixtures’ ρf, VFA, and Sa was the Weibull distribution, that of the Vbe indices was the Normal distribution, that of the VMA in asphalt mixtures was the Lognormal distribution, and that of VV was the Gamma distribution, which can provide a reference for the design and construction of highways’ pavement in this areas.

Development of a simple and efficient oil-soluble nanocatalytic system for aquathermolysis upgrading of heavy crude oil

Catalytic aquathermolysis is one of the key and cost-effective chemical method for recovering heavy oil. This process transforms the asphaltene and resin compounds of the oil into lighter fractions. Oil-soluble transition metal-based catalysts have been reported as efficient catalysts that improve the viscosity reduction efficiency of the aquathermolysis process. Previous studies have mainly focused on using long alkyl chains as oil-soluble ligands to prepare the catalysts. However, aromatic ligands that effectively interact with asphaltene and resin fractions have not been extensively studied. In other words, the molecular structure of ligand used in the catalyst synthesis significantly changes its activity in aquathermolysis. This study aims to fill this gap using catechol as a novel ligand to develop oil-soluble catalyst (Ni-OSC), which can interact with heavy oil fractions during aquathermolysis. Ni-OSC decreased the content of resin and asphaltene by 32.1% and 26.5%, respectively, and increased the amounts of saturated and aromatic hydrocarbons by 19.6% and 22.9%, respectively, compared to heavy oil. Moreover, a GC–MS study indicated that low molecular weight hydrocarbons in the composition of heavy oil increased, and the relative content of alkanes raised to 79% in the presence of Ni-OSC. The catalyst also increased the concentration of alkylbenzenes and naphthalenes in the composition of aromatic compounds, improving the quality and recovery of heavy oil. Furthermore, the viscosity of heavy oil was considerably reduced, and a maximum hydrogen to carbon ratio of 2.03 was observed in Ni-OSC system. To the best of our knowledge, this is the highest reported hydrogen-to-carbon ratio for catalytic aquathermolysis of heavy oil using oil-soluble catalysts.