Cracking Of Oil Research Articles

Pressure Source Model of the Production Process of Natural Gas from Unconventional Reservoirs

This work is focused on developing a computational model to predict the production rate and pressure evolution of natural gas from unconventional reservoirs, particularly shale gas deposits. The model is based on the principle of conservation of mechanical energy and was developed from the transient solution of Bernoulli’s equation. This solution was obtained by computing the pressure evolution in the well resulting from the combined action of extracting the free gas and of gasification from kerogen. The transient behavior of gas production by hydraulic fracturing was calculated by numerically integrating Bernoulli’s equation. The curves representing gas flow evolution were considered as a series of stepwise steady states under a constant gas flow rate, similar to the pressure–time curves. These time steps were connected by instantaneous drops in pressure or gas flow rates. On the other hand, the delayed release of the adsorbed and dissolved gas in the kerogen was accurately calculated by introducing a semi-empirical gas pressure source term into the gas well pressure equation. The effect of this source is to gradually increase the gas pressure in the reservoir, emulating the gas release mechanisms from the organic matter. Model validation was based on production data from the unconventional reservoirs Eagle Ford, U.S.A., and Burgos basin, México. The initial measured gas production rate was used to determine a global friction factor of the gas flowing out from soil cracks and ducts. Additionally, measured production rate data were used to determine the coefficients of the source term function. Pearson correlation coefficients of 0.97 and 0.96 were obtained for Eagle Ford and Burgos basins data, respectively. In contrast, the corresponding coefficients calculated from the traditional Arps’ model were 0.89 and 0.5, respectively. The present pressure source model (PSM) represents a new approach to characterize the process of gas production from unconventional reservoirs, proving to be accurate in forecasting both the gas flow rate and pressure evolution during gas production. The postulated pressure source term was shown to mimic the desorption and diffusion kinetics, which release free gas from the kerogen.

Microscopic Mechanisms and Evolution Models of Crack Development in an Expansive Soil under Conditions of Rainfall Evaporation Cycles

Expansive soil is a special soil type that undergoes volume expansion during hygroscopicity and volume contraction during dehumidification. In this study, the effects of rainfall–evaporation cycles on the microscopic pores and cracks of expansive soils under different rainfall intensities were analyzed by simulating light rainfall, medium rainfall, and high-temperature drought environments using nuclear magnetic resonance (NMR) technology and image processing methods. The results showed that the micropores and small medium pores of the expanded soil gradually evolved into macropores during the cycling process, especially under stronger rainfall conditions. In addition, as the number of cycles increased, the expanded soil showed irrecoverable pore changes, which ultimately led to the scattering damage of the soil. By processing the surface crack images of expansive soils, the process of crack development was categorized into four stages, and it was found that the evaporation cycle of medium rainfall intensity caused the main cracks of expansive soils to develop more rapidly. A quantitative relationship model between the average crack width and the number of cycles as well as porosity was constructed, and the regression coefficient of determination R2 reached 0.98, 0.96, and 0.84, respectively. This study simulates the effects of real rainfall conditions on expansive soils and investigates the mechanism and evolution of cracks in expansive soils, which is of great theoretical and practical significance.

Source apportionment of PM2.5 episodes in the Taichung metropolitan area, Taiwan

To analyze the physicochemical mechanisms affecting the variation in fine suspended particulate matter (PM2.5) concentrations in Taichung City, the largest city in central Taiwan (the second largest city in Taiwan), during a high-pollution event from November 3 to 6, 2021, we applied the sulfur tracking method (STM) and integrated source apportionment method (ISAM) of the WRF/CMAQ model to simulate the impacts of various emission sources. The sources of pollution in Taichung City are very similar, which shows that the impacts of point, line, and area sources should not be neglected in addition to the boundary conditions. SO42− is mainly generated from point emissions and the production of H2O2, Fe, Mn, and O3. NO3− is also mainly generated from point sources in Taichung City, with HNO3 being the main source at noon and ANO3 at other times of the day. NH4+ is mainly generated from area sources in Taichung City. OM is more complex, mainly originating from line sources in Taichung City and other sources, such as point/area emissions in Taichung City and other emissions from Changhua County. The most important mechanism is low-volatility/semivolatile oxidized combustion of OC at noon, followed by low-volatility/semivolatile POA, which is produced in the morning or evening. EC mainly originates from line sources in Taichung City and Changhua County. In other nearby counties, EC is dominated by local emission sources. In addition, when the concentration of PM2.5 is high, the Neutralization Ratio (NR) is high and PM2.5 is relatively neutral or slightly alkaline. On the contrary, when the concentration of PM2.5 is low, the NR is lower than 1 and the aerosol is acidic. Besides, this study used positive matrix factorization (PMF), which indicates that the PM2.5 at the UAPRS originated from eight kinds of pollution, namely, windblown dust, oil cracking, iron and steel industry, sea salt, transport, Cl− containing exhaust, biomass burning, fossil combustion containing abundant SO42− and the heavy oil refining and coal combustion industry. The direction of the source of pollution can be traced by a conditional bivariate probability function (CBPF). Overall, fossil fuel combustion, mainly involving sulfate, is the largest source of pollution, with the heavy oil refining and coal combustion industry contributing less, and the remaining factors contribute relatively evenly.

Deactivation and regeneration dynamics in hierarchical zeolites: Coke characterization and impact on catalytic cracking of vacuum gas oil

This study investigated the deactivation and regeneration of hierarchical zeolites in vacuum gas oil conversion, aiming to reach the equilibrium state seen in fluidized bed catalytic cracking (FCC). The research utilized various characterization techniques to analyze the properties of zeolites before and after coking and regeneration. Zeolite Y-0.20-S was found to have the highest gasoline selectivity and quality, mirroring industrial yields, and displayed notable stability across deactivation/regeneration cycles. Higher mesopore concentration in zeolites led to increased coke selectivity and better resistance to deactivation. The study observed a dominance of aromatic coke with a higher degree of condensation in these zeolites. Despite coke deposition affecting acid and textural properties, the regeneration process effectively restored these characteristics, proving its efficiency. The zeolites with greater mesoporosity retained their fundamental properties responsible for activity and selectivity, highlighting the importance of selecting materials that provide high conversions and maintain stability and product selectivity over multiple cycles. The Y-0.20-S zeolite, in particular, was identified as a promising candidate for commercial catalyst development for gasoline production, contributing to the FCC process's energy efficiency.

Response optimisation of TiO2-supported bimetallic NiCo catalyst for the cracking and deoxygenation of waste cooking oil into jet-fuel range hydrocarbon fuels under non-hydrogen environment

Waste cooking oil is a sustainable feedstock that can be utilised to produce biojet fuel via the hydrodeoxygenation process. However, the need for hydrogen for the hydrodeoxygenation process incurs high cost. In the present work, a type of bimetallic catalyst that can deoxygenate and selectively crack free fatty acids under hydrogen-free conditions was developed. The NiCo/TiO2 catalyst was prepared via the impregnation of varying amounts of Ni and Co salts onto TiO2. Optimisation of the production conditions was performed via response surface methodology based on the Box-Behnken experimental design to maximise the deoxygenation and biojet fuel yield. A maximum deoxygenation yield of 83.13 % with 44.5 % biojet fuel selectivity was obtained from the experiment and optimisation based on Box-Behnken design (R2 > 0.9). Incorporation of Ni and Co onto TiO2 reduced the surface area of the catalyst, but active metal dispersion significantly improved the deoxygenation performance and biojet fuel selectivity. The viscosity, flash point, freezing point and net heat of combustion value of the liquid product were within the jet fuel standard specifications. Overall, the study shows the potential of bimetallic NiCo/TiO2 catalyst in waste cooking oil deoxygenation for biojet fuel production.

Cracking in compacted expansive soils under unidirectional wet-dry cycles: insights from X-ray computed tomography

Cracking in compacted expansive soils under unidirectional wet-dry cycles: insights from X-ray computed tomography

Insight into the initiation and propagation mechanism of desiccation cracking in clayey soil from DEM simulations

Desiccation cracking, a common natural phenomenon, significantly affects the mechanical and hydraulic properties of clayey soils. This study employs 3D Discrete Element Method (DEM) to investigate the initiation and propagation mechanisms of soil desiccation cracking. By integrating water evaporation at the soil surface and water transportation between soil grains into a traditional DEM model, we unveil a sequential and hierarchical pattern in the development of desiccation cracks. Initially, micro cracks proliferate and coalesce in regions of soil defects characterized by the lowest coordination numbers, leading to the genesis of primary cracks. Subsequently, a complex network of cracks propagates, governed by the interplay between cracking and the redistribution of the tensile stress field. As desiccation advances, the detachment of soil from the bottom wall and an increase in soil strength contribute to the stabilization of the crack network. Notably, the hierarchical nature of desiccation cracking is predominantly shaped by initial soil defects and subsequently refined by stress concentration within the soil clods, correlating with changes in the length-to-height ratio of the soil clods.

Effects of vetiver root on cracking of expansive soils and its mechanistic analysis

The study investigated the reinforcing effect of vetiver root on soil by conducting outdoor planting tests and indoor root tests. The cracking indexes of soil specimens with varying root contents were analyzed, and a statistical model was established to determine the relationship between the cracking indexes, the number of dry and wet cycles, and the root content. The study revealed the crack evolution law of vetiver-reinforced expansive soil. The study explored the mechanism of the vegetation root in inhibiting the cracking of expansive soil and determined the optimal planting density of vetiver grass through outdoor planting tests. The results indicate that: The surface crack rate (CR), total crack length (CL), and crack number (CN) in the root-soil specimen exhibited exponential growth with an increase in the number of wet and dry cycles. This growth was more pronounced during the first and second cycles. The vetiver root could effectively reduce soil crack formation, and the specimen's cracking resistance is positively correlated with the root content. With the root content increased, the CR, CN, and CL decreased. The logistic model is suited to the CL of added root soil. The logistic model is more suitable for the growth model of the CR of the expansive soil with low root content, while the Boltzmann model is more suitable for the growth model of the CR of the expansive soil with high root content. Width of crack (CW) is better suited to the DoseResp growth model. The Boltzmann model is more applicable to the CN in expansive soils with low reinforcement, while the logistic growth model is more suitable for the development of CN above 0.21% root content. The development of the crack network was influenced by two key factors: the root content and the number of wet and dry cycles. Under the condition of planting roots, the development of crack networks in expansive soil differs from that of expansive soil with added roots, and there is no clear pattern to follow. The inhibitory effect of the vetiver root on cracking of expansive soil is related to the planting density of vetiver.

Migration of Microplastics in the Rice–Duckweed System under Different Irrigation Modes

Microplastic (MP) pollution in agriculture is garnering growing concern due to its potential detrimental impact on soil properties and crop growth, particularly affecting staple food crops such as rice. Irrigation plays a crucial role in the migration of MPs. However, limited research has focused on how different irrigation modes affect the migration of MPs in paddy fields. To simulate real-world conditions, in this experiment, two different irrigation modes were set: shallow–frequent irrigation (FWI, I0) and controlled irrigation (CI, I1). The experiment also included treatments with and without duckweed (D0 and D1, respectively), as well as treatments with and without MPs (M0 and M1). This resulted in a total of eight treatments: I0M0D0, I0M0D1, I1M0D0, I1M0D1, I0M1D0, I0M1D1, I1M1D0, and I1M1D1. Our findings indicated that compared to CI, FWI significantly increased the MP concentration in the leakage but reduced the numbers of MPs in the first soil layer and adhered by duckweed. Notably, dry–wet cycles under CI induced soil cracking, and the MP concentrations in cracked areas were significantly higher than those of crack-free soil. Moreover, compared with the MP-free treatment, MP treatments significantly influenced rice root growth, such as enhancing the average root diameter by 13.44%, root volume by 46.87%, root surface area by 30.81%, and biomass aboveground by 26.13%, respectively. The abundance of some microorganisms was also significantly influenced by the relative mobility (RM) of MPs. Furthermore, the root length was positively correlated with Planctomycetota. Meanwhile, Actinobacteriota was negatively correlated with the root surface area, root volume, and branch number, and Bacteroidota was negatively correlated with the number of root tips. However, further research is needed to elucidate how MPs influence microorganisms and, in turn, affect rice root growth.

Selective production of phenol from the end-of-life wind turbine blade through catalytic pyrolysis

This study employed catalytic pyrolysis to enhance the selectivity and yield of phenol in the pyrolysis oil derived from the end-of-life wind turbine blade (WTB). It was confirmed that the NiO(10)/Al2O3 catalyst exhibited the best activity, reaching a phenol selectivity of 28.57 % at 500 °C with a heating rate of 10 °C/min. Furthermore, a competitive phenomenon between the catalytic formation of phenol and that of gaseous products was observed. Characterization results indicated that at lower loading content of NiO on the Al2O3 carrier, NiAl2O4 crystals tended to form preferentially, which reduced catalyst activity by covering surface strong acid sites. With increasing the loading content of NiO, saturation of NiAl2O4 formation occurred, and free NiO crystals became dominant. This resulted in the creation of abundant Lewis acid sites, enhancing the catalytic formation of phenol. Whilst, excessive accumulation of free NiO crystals increased strong acid sites and significantly generated lattice oxygen, promoting the cracking of pyrolysis oil to gaseous products, which was detrimental to phenol enrichment but facilitated the production of H2-rich syngas. The conclusions offered valuable insights for upgrading pyrolysis products derived from epoxy resin polymers during the recovery of end-of-life WTB.

Zn-doped bentonite catalysts for waste engine oil cracking: Thermal treatment offers a cleaner alternative to acid activation

This study investigates the cracking of waste engine oil (WEO) using bentonite clay (BC) activated through acid and thermal methods, as well as with Zn-doped BCs. Acid activation with 1 M HCl and Zn doping did not alter the BC catalyst’s structure. XRD and SAED analyses confirmed the crystallinity, while TEM showed partial destruction of the layered structure. XRF analysis indicated reduced Al and Si content upon Zn-doping due to high cation exchange capacity. Zn-doping decreased surface area and pore volume but increased acidic sites in acid-treated catalysts, although Zn suppressed these sites in calcined BC. Zn-doped catalysts displayed higher thermal stability. Cracking WEO at 450 °C for 45 min, with and without catalysts, yielded high liquid product recovery (72.6 %–82.8 %), primarily carboxylic acids and aromatics. This demonstrates the potential of Zn-doped BC as an effective catalyst for converting WEO into valuable products, aiding waste management and resource utilization.

Reaction network and kinetic modeling for the direct catalytic cracking of Arabian light crude oil to chemicals

We investigate the catalytic cracking of Arabian light crude oil into chemicals. A kinetic model has been established for an in-house developed catalyst using a micro-activity testing unit under a wide temperature range (525–650 °C) and various catalyst-to-oil ratios (0–4.14). Our conditions are adjusted to promote light olefins and propylene-to-ethylene ratio. We trained different reaction networks with the experimental data to calculate the kinetic parameters and, at the same time, select a statistically relevant model. The most representative model, with eight lumps and forward–backward first-order reactions, enables the acceptable prediction of the yield of chemicals (light olefins). The obtained kinetic parameters suggest that diesel and gasoline fractions are important intermediates in which forward reactions are preferred due to lower activation energy requirements and faster rate constant. The model was validated by reparametrization using Arabian extra light data.

Insights into Si/Al ratios for enhanced performance of β-zeolites in thermocatalytic cracking of crude oil to light olefins

The escalating demand for key petrochemicals, particularly ethylene and propylene, underscores the critical need for proficient catalysts in crude oil conversion processes. Attaining high propylene selectivity necessitates catalysts with superior adsorption capacity, thermal stability, moderate surface acidity, and pores large enough to facilitate the diffusion of larger crude oil molecules. In the present study, three different BEA Zeolites (β-zeolite) catalysts were successfully synthesized by hydrothermal method and used for catalytic cracking of Arabian Light crude oil to produce valuable petrochemical products, such as propylene, ethylene, and naphtha. The catalysts were characterized using 27Al and 29Si NMR, NH3-TPD, BET, XRD, TGA, FTIR, XRF, and FE-SEM. The thermocatalytic cracking of Arabian Light crude oil was evaluated in a fixed-bed microactivity test (MAT) unit between 550 and 600 °C. The as-prepared β-zeolite with a Si/Al ratio of 50 exhibited better catalytic activity in the catalytic cracking of Arabian Light crude oil compared to counterparts with Si/Al ratios of 35 and 65, This superiority can be attributed to its optimal combination of surface acid site distribution, textural properties, surface morphology, and high adsorption capacity. The highest feed conversion (83.4 %) and selectivity to propylene (16.11 %) were attained using β-zeolite with a Si/Al ratio of 50 at 600 °C. Importantly, our findings suggest that these catalysts hold significant potential, rivalling primary MFI catalysts like ZSM-5 commonly employed in similar reactions. This underscores their promise as catalysts of choice in the realm of catalytic cracking processes, paving the way for advancements in petrochemical production.

Solid bitumen Rhenium-Osmium (Re–Os) isotope geochronology and existing problems: Sampled of Sinian-Cambrian gas reservoir in Sichuan Basin, China

Understanding the key timings related to petroleum evolution is crucial for optimizing exploration targets and assessing oil/gas resources, attract petroleum geologists’ attention worldwide. Recently, hydrocarbon (oil and bitumen) Re–Os isotope dating has been innovatively applied to constrain the timing related to oil/gas generation, however, the resulting Re–Os isochron ages can be complex and challenging to interpret. This study utilizes various geochemical and geochronological data from Sinian to Cambrian natural gas reservoirs in the Sichuan Basin to reconstruct the hydrocarbon evolution process and discuss the significance of different bitumen Re–Os dating results. The gas accumulation in the Sinian-Cambrian reservoirs experienced four stages of evolution: (1) initial oil generation during the Ordovician to Silurian periods, (2) secondary oil generation during the Triassic period, (3) gas generation through thermal cracking of liquid oil from the Jurassic to Cretaceous periods, and (4) gas reservoir redistribution since the late Cretaceous. The Re–Os dates (ca. 485 Ma) of low maturity and biodegraded bitumen from the western Sichuan Basin record the oil generation during the Ordovician before the Caledonian tectonic event. The Re–Os dates (ca.184–128 Ma) of highly mature bitumen associated with MVT Pb–Zn deposits in northern Sichuan Basin provide insights into both liquid oil-cracking and thermochemical sulfate reduction (TSR) processes. The complex Re–Os dates (ca.414 Ma, ca.154 Ma) of highly mature bitumen from the central Sichuan Basin may represent different periods related to either oil or gas generation. Future studies should explore the genetic type, maturity, thermal cracking, or TSR degrees of bitumen to better understand the significance of Re–Os dates.

Experimental study on improving the performance of imitation earthen site soil in carbon dioxide environment

This study aims to explore the performance of lime-treated soil for repairing the lime soil of the earthen city wall of Kaifeng and to standardize the construction technology of lime-treated soil. The research comprehensively considered factors such as carbonation time, lime particle size, aging conditions, and lime content, and conducted various tests and analyses including triaxial mechanical properties, surface crack analysis, particle size distribution, pH measurement, composition analysis, and electron microscopy on different samples. The results indicate that the significant effect of high-concentration CO2 carbonation enhances the chemical reactions of lime soil, and an appropriate carbonation process can strengthen the bonding and density between soil particles. Under the maintenance condition of 5 % CO2, with increasing carbonation time, the crack ratio, average crack length, and average crack width of the samples decreased. Cohesion and internal friction angle of the samples exhibited an initial increase followed by a decrease, while shear strength of the samples increased by 22.93 %–75.09 %. The lime particle size has a critical impact on the formation of cracks in lime soil. With increasing lime particle size, the crack ratio, average crack length, and average crack width of the samples increased. Cohesion and internal friction angle of the samples gradually increased with increasing lime content. The increase in crack ratio, average crack length, and average crack width during natural curing of lime-treated soil samples was proportional to the lime content. Appropriate carbonation time, smaller lime particle size, and curing conditions with 5 % CO2 contribute to improving the particle size distribution of lime-treated soil samples, reducing surface cracks, and enhancing performance. However, prolonged carbonation may lead to larger lime particle size, resulting in rough and loose particles, disorganized arrangement of CaCO3 crystals, and the inability to form a cross-linked network skeleton, causing a reduction in shear strength of the samples. These research findings provide important theoretical basis and construction technology guidance for the application of lime-treated soil combined with CO2 carbonation in repairing earthen city walls.

Improvement of earthen dikes with binders: a civil engineering advancement for agricultural irrigation and drought mitigation in Algeria

In recent decades, Algeria has faced significant challenges due to climate change, resulting in cracks in agricultural soils and degradation of the vegetation layer, especially during unusual summer rains. Dikes play a crucial role in preserving this vegetation layer, allowing farmers to restore soil integrity and utilize dikes as earth barriers for crop irrigation and animal watering.Within civil engineering, dikes are often classified as either hydraulic or geotechnical structures, typically constructed using compacted earth, especially in non-draining soils like clays or soft soils. It has been observed that accumulation of mud or water can compromise their structural integrity partially or completely.To address these issues, this study focuses on presenting reinforcement systems for earth-built dikes using commonly used binders in the Algerian market such as Portland cement, lime, gypsum, etc. Specific calculations are conducted to assess the strength, mechanical behavior, and resilience of each dike type based on soil type, reinforcement method, and concentration. This approach aims to enhance the mechanical properties of dikes and optimize soil characteristics, offering solutions to strengthen the irrigation and agricultural sector, potentially yielding significant economic benefits for the country.

Catalytic Cracking of Crude Waste Plastic Pyrolysis Oil for Enhanced Light Olefin Production in a Pilot-Scale Circulating Fluidized Bed Reactor

Catalytic Cracking of Crude Waste Plastic Pyrolysis Oil for Enhanced Light Olefin Production in a Pilot-Scale Circulating Fluidized Bed Reactor

Development Characteristics and Mechanism of Crack in Expansive Soil under Wet–Dry Cycling

Development Characteristics and Mechanism of Crack in Expansive Soil under Wet–Dry Cycling

Estimation of catalytic cracking of vacuum gas oil by ZSM-5- and β-zeolite-containing two-layered and novel three-layered hierarchical catalysts using Curie point pyrolyzer

ZSM-5- and β-zeolite-containing two-layered hierarchical catalysts (2 L-Z and 2 L-β) were prepared using a template of malic acid and novel three-layered hierarchical catalysts were also prepared combining mesoporous silica derived from the gel skeletal reinforcement (GSR) method with hexamethyldisiloxane (HMDS) - acetic anhydride (AA) as reinforcing agents. 2 L-Z and 2 L-β catalysts contained mesoporous silica of 50 wt% and microporous zeolite of 50 wt% and were called 2 L-Z-(Z50) and 2 l-β-(Z50) in which the amount of zeolite is shown in parenthesis. 3 L-co-gel and 3 L-mix, two types of three-layered hierarchical catalysts, were prepared by making GSR-silica in the presence of a 2 L catalyst for the former and by combining GSR-silica-gel with 2 L catalyst for the latter. 3 L catalysts contained 50 wt% of the 2 L catalyst and 50 wt% large-mesoporous GSR-silica and revealed three layered properties of microporous zeolite, small mesoporous silica and large mesoporous silica. Signals of zeolite crystals and amorphous phase were observed in XRD measurement for 3 L catalysts. Both smaller size of mesopores and larger size of mesopores were observed in N2 adsorption-desorption measurement. Vacuum gas oil (VGO) was catalytically cracked using 2 L and 3 L hierarchical catalysts with the use of Curie point pyrolyzer (CPP) method. ZSM-5-containing 3 L catalysts exhibited the lower conversions than corresponding 2 L catalyst, kaolin-mixed catalyst and ZSM-5 single while 3 L-co-gel-β-(Z25), which included 25 wt% of β-zeolite, exhibited the highest activity among β-zeolite-containing catalysts. The higher selectivity for p-xylene in xylene mixture was detected in catalytic cracking using 3 L-co-gel-Z-(Z25) and 3 L-mix-Z-(Z25) catalysts. When the relative activity against XRD integral intensity and amounts of acid sites was plotted against average pore diameter derived from N2 adsorption-desorption measurement, the strong correlation was observed, suggesting that the intrinsic activity of active sites of zeolite could be related to the pore size of the whole catalyst.

THERMAL TRANSFORMATIONS OF MALTENES AND OILS FROM HEAVY METHANE BASE CRUDES

The paper considers changes of composition of oils and maltenes during thermal cracking process. The oils and maltenes (mixture Oils+Resins) were isolated from crudes from two oil fields: Zyuzeevskoye (Republic of Tatarstan) and Zuunbayanskoye (Mongolia). Both crudes relate to methane type, but differ by content of saturated, aromatic hydrocarbons, resins, asphaltenes and sulfur. Cracking of oils and (O+R) mixtures was carried out at 450 °С for 120 min in isothermal mode. Data on the mass balance of process, composition of gaseous and liquid cracking products were obtained. It was shown the С1-С5 hydrocarbons are predominate in the composition of gaseous cracking products of oils and (O+R) mixtures. Independent of cracking object their content changes in a series: C1 > C2 > C3 > С4-С5. The dynamics of group hydrocarbon composition changes in thermolysates was studied. It was shown the thermal transformations of hydrocarbons steer in the direction of destruction reactions during cracking of oils with high content of saturated hydrocarbons, as it indicated by gaseous products yield. Condensation reactions are dominated during cracking of oils, in composition of which aromatic hydrocarbons are prevail. It was shown the addition of resins into the complex multicomponent mixture of hydrocarbons leads to directivity change of cracking free radical reaction behavior. Differences in structural-group characteristics of average resins molecules reflect not only on the yield of solid and gaseous cracking products of (O+R) mixture, but also affect on the directivity of hydrocarbons thermal transformations. Moreover it is impossible to exclude the effect of differences in the content of saturated and aromatic hydrocarbons in the composition of oils on the components thermal transformations during cracking process of (O+R) mixtures. For citation: Voronetskaya N.G., Pevneva G.S. Thermal transformations of maltenes and oils from heavy methane base crudes. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 8. P. 59-67. DOI: 10.6060/ivkkt.20246708.4t.