Cracking Of Crude Oil Research Articles

Investigation of metalloporphyrins in Duri crude oil asphaltene fraction

Metalloporphyrins are a compound that leads the contaminant in catalytic cracking of crude oil. This study aims to investigate the metalloporphyrin in crude oil from Duri, Riau, Indonesia. The extraction process yielded maltene and asphaltene up to 71.87 % and 1.07%, respectively. Asphaltene fraction was extracted by soxhlet using methanol solvent. The separation of asphaltene fraction was perfomed by column chromatography using mixing of toluene: chloroform: methanol (5:5:1) eluents. The Fourier Transform Infrared (FTIR) spectrum of asphaltene indicated the presence of a pyrolle ring at 800 cm−1 in the fingerprint region as a porphyrin-formed group. The UV-Vis absorption spectra of methanol separation showed free porphyrin at 580 nm and metalloporphyrins at 500–700 nm. The Microwave Plasma-Atomic Emission Spectrometer (MP-AES) qualitative analysis of asphaltene fraction showed the presence of vanadium, nickel, and iron. The Liquid Chromatography-Mass Spectrometry (LC-MS) analysis on asphaltene 15th fraction showed the presence of C34H39N4VO2 compound.

Thermal and catalytic cracking of whole crude oils at high severity

The catalytic and thermal cracking of three types of whole crude oils, having API gravity at 34° (AL), 39° (AXL) and 51° (ASL), were investigated via a fixed-bed micro-activity test (MAT) unit at high temperature between 600 and 650 °C. Equilibrium FCC catalyst (E-Cat)/ZSM-5 additive was used for catalytic cracking tests at 30 s and catalyst/oil (C/O) ratio of 2.0–6.0. For both thermal and catalytic cracking of all crude oils, the increase in reaction temperature resulted in higher conversion and enhanced yields of C2-C4 light olefins, LPG, coke, and dry gas at the expense of naphtha, heavy cycle oil (HCO), and light cycle oil (LCO). In thermal cracking, the yields of C2-C4 olefins at 650 °C were as follows: AL (22.8 wt.%) > AXL (19.0 wt.%) > ASL (18.8 wt.%) associated with naphtha yields of 34.4, 38.1 and 48.0 wt.%, respectively. Compared with thermal, catalytic cracking over E-Cat/ZSM-5 enhanced conversion, doubled the yields of light olefins and showed an increase in aromatics content of naphtha fraction. Contrary to thermal cracking, the yields of C2-C4 olefins in catalytic cracking were as follows: ASL (42.9 wt.%) > AXL (41 wt.%) > AL (39.1 wt.%) associated with naphtha yields of 31.7, 27.5, and 23.0 wt.%, respectively.

Experimental analysis on heating of oil inclusion in Gucheng area of East Tarim

In this paper, the formation and preservation conditions of crude oil cracking gas reservoirs are analyzed by heating experiments of oil inclusions. The study of tectonic development history shows that Gucheng low uplift mainly undergoes three evolutionary stages: early extension, middle uplift and late subsidence. Up to the end of Devonian and early Hercynian, the southeastern Altun compression resulted in warping plate uplift and denudation in Gucheng area, with denudation thickness of about 1000-2800m.The experimental results show that no inclusion rupture occurs during the whole process of heating to 600?.It was observed that the phase state of inclusions changed obviously during heating process, and the fluorescence of inclusions weakened obviously after natural cooling, reflecting the cracking process of crude oil. The results of high resolution laser-raman spectrum measurements of oil inclusions after heating experiments show that methane is the main component of gas inclusions, while carbon dioxide is small. According to the microscopic comparison of oil inclusions before and after heating, it is inferred that the sample has not undergone this high temperature process. Theoretically, it is assumed that oil and gas inclusions will rupture when heated to a certain temperature. It is possible that this experiment did not reach the limit temperature of inclusion rupture.

Genetic types of natural gas and gas-source correlation in different strata of the Yuanba gas field, Sichuan Basin, SW China

The chemical compositions and stable carbon and hydrogen isotopic compositions of natural gases in different strata of the Yuanba gas field in the Sichuan Basin were analyzed to investigate their genetic types and source. Natural gases from the Permian Changxing and Triassic Feixianguan formations have dryness coefficients higher than 0.995 and contain H2S in most gas samples, having a positive correlation between the H2S and CO2 contents. The identification of gas origin and gas-source correlation from this study indicate that natural gas in the Ziliujing Formation and most gas samples from the Xujiahe Formation are coal-type gas produced from primary cracking of kerogen, and they are self-sourced reservoirs in relatively independent systems. The natural gases in the 1st and 2nd members of the Xujiahe Formation were mixed with minor amounts of oil-type gas from argillaceous carbonate rocks in the Leikoupo Formation. In addition to the self-accumulated oil-type gas in the Leikoupo Formation, natural gas mainly came from the overlying or lateral source rocks in the Xujiahe Formation. The H2S-bearing natural gases in the Changxing and Feixianguan formations were produced by the cracking of crude oil from source rocks in the underlying Wujiaping Formation, with partial contributions from certain local source rocks in the Permian Dalong Formation. The H2S-bearing natural gas has undergone the thermochemical sulfate reduction (TSR) which were dominated by heavy hydrocarbons. The high δ13C values of CO2 in these gas reservoirs mainly result from the interaction between acidic fluids and carbonate rocks in the reservoirs.

Origin of conventional and shale gas in Sinian–lower Paleozoic strata in the Sichuan Basin: Relayed gas generation from liquid hydrocarbon cracking

Large amounts of natural gas have been discovered recently, both in carbonate reservoirs and in shales in the Sinian–Silurian strata of the Sichuan Basin, southern China. Although numerous studies have been conducted to learn about the accumulation of conventional and shale gas, the gas generation history, the origins of the two types of gas, and gas resources in the basin remain unclear. In this study, the hydrocarbon generation histories of Cambrian and Silurian source rocks were reconstructed on the basis of thermal history and hydrocarbon generation kinetic parameters. Intensive cracking of crude oil to generate considerable amounts of secondary cracking gas in Silurian and Cambrian formations occurred during deep burial. The high abundance of overmature pyrobitumen in carbonate reservoirs and shale demonstrates the occurrence of large-scale in situ cracking of liquid hydrocarbons. A mixing model was proposed to quantitatively determine the contribution of kerogen and oil-cracking gas in shale gas accumulations. The mixing of two thermogenic gases with different maturities resulted in a reversal and a rollover of the carbon isotope compositions of shale gas. Moreover, gas resources from the cracking of three occurrence states of liquid hydrocarbons—including dispersed residual bitumen in source rocks, dispersed oil outside the source, and accumulated oil in reservoirs—were evaluated in Sinian–Cambrian and Silurian petroleum systems in the Sichuan Basin, providing a guide for future deep gas exploration of similar formations in China and elsewhere.

Genesis and origin of natural gas in the Beidagang structural belt of Dagang oilfield

The south and north of Beidagang structure zone in Dagang oil field are Qikou sag and Banqiao sag respectively, it´s belong typical “two sag one uplift”, has abundant oil and gas source, developing reservoir condition is good. From now it has find various types of gas reservoirs in several heavy reservoirs and series of strata, so it has complex oil genesis and gas. This article collected a large number of natural gas samples systematically, launching a study on the composition and carbon isotope of natural gas, identifying the overall characteristics and causes of natural gas in Beidagang structure zone.Research shows in Beidagang structure zone, different heavy reservoirs and series of strata about composition and carbon isotope of natural gas are basically the same, methane contant is low, dry coefficient is small, spreading 0.8-0.89, belong typical wet gas. The distribution of methane and ethane carbon isotope are wide, insisting humic-type natural gas, sapropelic natural gas and biogas.Biogas are mainly distributed in Gangxi area, Banzhong, Bannan, Banbei, Tangjiahe, Baishuitou, Gangdong and Qianmiqiao area’s natural gas mainly is mainly the product of hydrocarbon source rock saprophytic organic matter mature stage in san-segment of Banqiao depression, Maxi ang Madong natural gas is the product of hydrocarbon source rock humus type organic matter mature stage of shahejie formation from Qikou depression. At present, the natural gas from the high over-maturity stage of the deep hydrocarbon source rocks in the depression is seldom distributed in the Beidagang structural belt, showing gas exploration in deep sag has a bright prospect.The high over mature stage natural gas in deep sag and Qikou depression Saproped-type hydrocarbon source rock crude oil cracking gas are important exploration target.

Geochemical characteristics of shale gas and its response to thermal maturity (Ro) in the Longmaxi formation, Dingshan area, Southeast Sichuan

The composition and carbon isotope distribution of shale gas from the Longmaxi Formation in the Dingshan area were measured, and their responses to thermal maturity (Ro) were analyzed. The results show that the shale gas is mainly composed of methane (97.98–98.99%), ethane, propane and nonhydrocarbon gases (N2 and CO2) and is an organic high temperature oil-type cracked gas. The wetness value [(C2+C3)/(C1+C2+C3) × 100%] ranges from 0.39% to 0.74%. The early (Ro > 1.3%) residual kerogen and crude oil cracking gas was mixed with the late (Ro > 2.0%) secondary cracking gas, resulting in the full inversion of the carbon isotope sequence (δ13C1 > δ13C2 > δ13C3).

Conceptual Coupled Process for Catalytic Cracking of High-Acid Crude Oil

To process high-acid crude oil by catalytic cracking technology, a coupled process (FCD–FCC) involving fluid catalytic deacidification (FCD) of high-acid crude oil over a spent catalyst and fluid c...

Origin and formation of deep and superdeep strata gas from Gucheng-Shunnan block of the Tarim Basin, NW China

Abstract A series of experiments, including natural gas molecular composition, carbon isotope analysis and fluid inclusion petrography and microthermometry were conducted to research the origin and formation of natural gases in the Middle Ordovician Yijianfang Formation and the Middle-Lower Ordovician Yingshan Formation, Gucheng-Shunnan block. Natural gases consist predominantly of methanes, with dry coefficients of 0.951–0.999 and have relatively heavy carbon isotopic signatures, with average δ13C1 and δ13C2 values of −36.4‰ and −32.5‰, respectively. The diagrams between δ13C-C1 versus C1/(C2 + C3) and methane carbon isotope versus ethane-propane isotopic separation suggest that these gases are oil-associated thermogenic gas from type Ⅱ kerogen with high thermal evolution extent of the source rocks. The empirical correlation of ln(C1/C2) and ln(C2/C3) indicates natural gases originated from crude oil cracking. Natural gases in the Gucheng block and the Shunnan block have properties similar to those of oil-cracking gases in the Eastern Lungu block and the Eastern Tazhong block. Due to reservoir temperatures being lower than formation temperatures of the gases and the potential of higher mature source rock being almost exhausted, natural gases originated predominantly from the cracking of deep paleo-oil pool rather than dispersive dissoluble organic matter in the source rocks. The comprehensive analysis of thermal evolution history, burial history, fluid inclusions and geological conditions suggest that natural gases formed during Himalayan stage. Deep oil-cracking gases accumulated in the Ordovician reservoir through migration along faults. Therefore, deep-seated natural gases have great potential for exploration.

Conversion of Arabian Light Crude Oil to Light Olefins via Catalytic and Thermal Cracking

The thermal and catalytic cracking of Arabian Light crude oil, which has a density of 34° API, were evaluated in a fixed-bed microactivity test (MAT) unit between 550 and 650 °C. For the catalytic cracking, two catalysts were used, a steamed commercial MFI catalyst (M-cat) and an equilibrium FCC catalyst (E-cat). Thermal and catalytic cracking were compared at the same conversion, 34%, at 650 °C. For both, as the temperature increased, the yields of light olefins, LPG, dry gas, and coke increased, associated with a consistent decrease in heavy ends (LCO and HCO). The naphtha yield for catalytic cracking decreased as temperature increased; however, for thermal cracking, it was nearly constant. The superiority of catalytic cracking over thermal cracking for the propylene yield was interpreted in terms of mechanisms of free radicals and carbenium ions. Thermal cracking gave a higher yield of ethylene. At high temperature (650 °C) and catalyst to oil (C/O) ratio of 4, the olefins yield decreased in the order ...

Catalytic Cracking of Light Crude Oil to Light Olefins and Naphtha over E-Cat and MFI: Microactivity Test versus Advanced Cracking Evaluation and the Effect of High Reaction Temperature

The catalytic cracking of light paraffinic crude oil with an API gravity of 51° was compared using two laboratory testing techniques, a fixed-bed microactivity test (MAT) unit and a fixed fluidized-bed advanced cracking evaluation (ACE) unit. Both units were operated using equilibrated FCC catalyst (E-Cat), MFI zeolite (ZSM-5), and E-Cat/MFI (equal mixture with MFI) at two temperatures (550 and 600 °C) and a constant catalyst-to-oil ratio of 4.0. Despite the different hydrodynamics in MAT and ACE reactors, both units gave similar catalyst ranking based on the conversion of 221+ °C feed fraction at 550 and 600 °C in the order of E-Cat > E-Cat/MFI > MFI, which is attributed to diffusion limitation of MFI catalyst. While both testing techniques showed variation in product yield structure (dry gas, LPG, naphtha, and unconverted 221+ °C) over the three catalysts, the ACE unit gave significantly higher coke yield compared with MAT. The highest yield of light olefins was obtained over E-Cat/MFI (29 wt %) at 600 ...

Main factors influencing the formation of thermogenic solid bitumen

Highly mature solid bitumen, a residue of oil cracking, is widespread in the lower Paleozoic paleo-oil reservoirs of southern China. Solid bitumen is not a simple, pure component, but rather a compositionally and structurally variable mixture of materials. This study investigated the formation of thermogenic solid bitumen and the effects of oil composition and reservoir environment. A series of seven gold-tube pyrolysis experiments were conducted: three used the main fraction groups (i.e., saturated, aromatic, and resin + asphaltene fractions) of crude oil to evaluate the effect of oil composition on the formation of solid bitumen during cracking; the other four tested the effects of water and pressure in reservoirs by simulating the cracking of crude oil under different reservoir conditions. Quantitative analyses of pyrolytic products (including methane, C2–C5 gaseous hydrocarbons, C6–C13 light hydrocarbons, C13+ heavy hydrocarbons, and solid bitumen) indicated that thermogenic solid bitumen formed at different stages of oil cracking, and its formation was clearly affected by oil composition. In contrast, water and pressure in the reservoir had little effect on the formation of solid bitumen.

Catalytic Cracking of Arab Super Light Crude Oil to Light Olefins: An Experimental and Kinetic Study

Catalytic cracking of Arab Super Light (ASL) crude oil (containing 46.1 wt % naphtha-range fraction) was studied over zeolite Y- (Y-Cat) and MFI-based (Z-Cat) catalysts at 500–575 °C. Experiments were conducted in a riser simulator by varying the residence times from 1 to 10 s. ASL crude oil and the cracked products were divided into heavy fraction, naphtha, and C1–C4 gases. Experimental results showed that additional naphtha is formed due to the cracking of the heavy fraction, and the formation of C1–C4 gaseous products occur mostly via cracking of naphtha. An increase in reaction time or temperature showed a more pronounced effect on the propylene yield compared to that of ethylene. Z-Cat produced more ethylene and propylene, which was attributed to its higher acidity, shape selectivity, and the higher hydrogen transfer reaction over Y-Cat. A three-lump model was appropriate for kinetic modeling of the catalytic cracking of ASL over Y-Cat. Comparison of the activation energies and rate constants showed ...

Separation and characterization of biofuels in the jet fuel and diesel fuel ranges by fractional distillation of organic liquid products

In this paper, we investigated the fractional distillation on bench scale of four organic liquid products (OLPs) obtained by thermal-catalytic cracking of crude palm oil using 5%, 10%, 15%, and 20% (w/w) sodium carbonate as the catalyst. The main objective of this work was to obtain biofuels similar to fuels derived from petroleum such as jet fuel and diesel fuel. Thus, the fractionation experiments were carried out at atmospheric pressure and in two distillation temperature ranges, 160–245 °C and 245–340 °C, obtaining two distilled fractions denominated green jet fuel and green diesel, respectively. The distilled fractions (biofuels) have been physical-chemical characterized by Officials AOCS and ASTM Methods regarding specific gravity at 20 °C, kinematic viscosity at 40 °C, corrosiveness to copper, acid value, saponification value, refractive index, and distillation curve. The chemical composition of distilled fractions has been determined by GC–MS. The results of the fractionation of the OLPs show that sodium carbonate is an excellent catalyst regarding yield and selectivity for the production, firstly of green diesel and secondly of green jet fuel. Most physical-chemical properties of green jet fuel and green diesel fractions are within limits established by ANP No. 37 for conventional jet fuel [aviation kerosene (QAV-1/JET A-1)] and ANP No. 65 for commercial diesel (diesel S10), respectively. The experimental distillation curve of the green jet and green diesel fractions are similar to the standard distillation curve of aviation kerosene and diesel S10, respectively. Results from GC–MS analysis revealed that the size of the hydrocarbon chains constituting the green jet fuel (C10-C15) and green diesel (C14-C17) fractions obtained in the present study are in agreement with the length of the chains of hydrocarbons established for aviation kerosene and diesel S10, respectively. In parallel, the increase of catalyst in the thermal-catalytic cracking process improved the yield, selectivity, physical-chemical properties and chemical composition of both biofuels. Therefore, the results presented in this paper indicate that green jet fuel and green diesel fractions can be used as a partial or total substitute for aviation kerosene and diesel S10, respectively.

Catalytic Cracking of Light Crude Oil: Effect of Feed Mixing with Liquid Hydrocarbon Fractions

The direct catalytic cracking of Arab Extra Light (AXL) crude oil was conducted in a microactivity test (MAT) unit at 550 °C, where product recycling was simulated by mixing feed and liquid products in varying proportions. The effect of AXL mixing with total liquid product (LP) or a mixture of light cycle oil (LCO) and heavy cycle oil (HCO) was investigated at various ratios to determine the dependence of light olefins yield on feed composition. It was observed that mixing the least amount of LP with AXL yielded ∼20.3 wt % light olefins and 39.6 wt % naphtha. The cracking of AXL and LCO+HCO yielded similar results as the case of cracking LP. A configuration of 100% recycle of liquid product without blending with AXL feed showed an increase in the yield of light olefins from 20 wt % to 29 wt % associated with a decrease in naphtha yield from 40 wt % to 27 wt %. A second configuration of 100% recycle of LCO+HCO without blending with AXL feed showed that the yield of light olefins increased from 20 wt % to 26 wt % associated with an increase in naphtha yield from 40 wt % to 50 wt %. The study has shown that the recycling of low-value heavy fraction (LCO+HCO) is a cost-effective means to supplement the AXL feed without loss in the yield of desired light olefins and naphtha.

Direct crude oil cracking for producing chemicals: Thermal cracking modeling

The direct cracking of crude oil is an interesting option for producing cheaply large amounts of petrochemicals. This may be carried out with catalyst and equipment similar to that of catalytic cracking, but at a temperature range between that of standard catalytic cracking and steam cracking. Thermal cracking will play a role in the conversion, but is rarely disclosed in experimental or modeling work. Thus, a crude oil and its fractions were thermally cracked and the products yields were modeled using a 9 lumps cracking scheme. It was found that heavy fraction cracks twice as fast as diesel fraction and ten times faster than gasoline fraction, with activation energies in the 140–200kJ/mol range. Selectivity to ethylene, propylene and butenes were found similar in the operating range explored.

In Situ Methylene Capping: A General Strategy for Efficient Stereoretentive Catalytic Olefin Metathesis. The Concept, Methodological Implications, and Applications to Synthesis of Biologically Active Compounds.

In situ methylene capping is introduced as a practical and broadly applicable strategy that can expand the scope of catalyst-controlled stereoselective olefin metathesis considerably. By incorporation of commercially available Z-butene together with robust and readily accessible Ru-based dithiolate catalysts developed in these laboratories, a large variety of transformations can be made to proceed with terminal alkenes, without the need for a priori synthesis of a stereochemically defined disubstituted olefin. Reactions thus proceed with significantly higher efficiency and Z selectivity as compared to when other Ru-, Mo-, or W-based complexes are utilized. Cross-metathesis with olefins that contain a carboxylic acid, an aldehyde, an allylic alcohol, an aryl olefin, an α substituent, or amino acid residues was carried out to generate the desired products in 47-88% yield and 90:10 to >98:2 Z:E selectivity. Transformations were equally efficient and stereoselective with a ∼70:30 Z-:E-butene mixture, which is a byproduct of crude oil cracking. The in situ methylene capping strategy was used with the same Ru catechothiolate complex (no catalyst modification necessary) to perform ring-closing metathesis reactions, generating 14- to 21-membered ring macrocyclic alkenes in 40-70% yield and 96:4-98:2 Z:E selectivity; here too, reactions were more efficient and Z-selective than when the other catalyst classes are employed. The utility of the approach is highlighted by applications to efficient and stereoselective syntheses of several biologically active molecules. This includes a platelet aggregate inhibitor and two members of the prostaglandin family of compounds by catalytic cross-metathesis reactions, and a strained 14-membered ring stapled peptide by means of macrocyclic ring-closing metathesis. The approach presented herein is likely to have a notable effect on broadening the scope of olefin metathesis, as the stability of methylidene complexes is a generally debilitating issue with all types of catalyst systems. Illustrative examples of kinetically controlled E-selective cross-metathesis and macrocyclic ring-closing reactions, where E-butene serves as the methylene capping agent, are provided.

Kinetic studies on extra heavy crude oil upgrading using nanocatalysts by applying CFD techniques

Abstract Regarding the growth of global energy consumption and the paucity of light crude oil, extracting and using heavy and extra heavy crude oil has received much more attention, but the application of this kind of oil is complicated due to its very high molecular weight. High viscosity and low flowability complicate the transportation of heavy and extra heavy crude oil. Accordingly, it is essential to reduce the viscosity of heavy and extra heavy crude oil through in-situ operations or immediate actions after extraction to reduce costs. Numerical simulations are influential methods, because they reduce calculation time and costs. In this study, the cracking of extra heavy crude oil using computational fluid dynamics is simulated, and a unique kinetic model is proposed based on experimental procedures to predict the behavior of extra heavy crude oil cracking reaction. Moreover, the hydrodynamics and heat transfer of the system and influence of nanocatalysts and temperature on the upgrading of crude oil are studied. The geometry of a reactor is produced using commercial software, and some experiments are performed to examine the validity and accuracy of the numerical results. The findings reveal that there is a good agreement between the numerical and experimental results. Furthermore, to investigate the main factors affecting the process, sensitivity analysis is adopted. Results show that type of catalyst and concentration of catalyst are the parameters that influence the viscosity reduction of extra heavy crude oil the most. The findings further revealed that when using a 25 nm SiO2 nanocatalyst, a maximum viscosity reduction of 98.67% is observed at 623 K. Also, a catalyst concentration of 2.28wt% is best for upgrading extra heavy crude oil. The results obtained through sensitivity analysis, simulation model, and experiments represent effectual information for the design and development of high performance upgrading processes for energy applications.

A study of the catalytic steam cracking of heavy crude oil in the presence of a dispersed molybdenum-containing catalyst

The features of the steam cracking of heavy crude oil in the presence of a dispersed molybdenumcontaining catalyst are studied. The effect of water, the catalyst, and process conditions on the composition and properties of the products of the thermal conversion of heavy crude oil is determined in experiments on thermal cracking, steam cracking, catalytic cracking in the absence of water, and hydrocracking. A complex analysis of the resulting products is conducted; the catalyst-containing solid residue (coke) has been studied by XRD and HRTEM. The effect of the process temperature (425 and 450°C) and time on the yields and properties of the resulting products is studied. The efficiencies of hydrocracking and steam cracking for the production of upgraded low-viscosity semisynthetic oil are compared; the fundamental changes that occur in the catalyst during the studied processes are discussed. Some assumptions about the principle of the catalytic action of the molybdenum-containing catalyst in the steam cracking process are made.

Catalytic steam cracking of heavy crude oil with molybdenum and nickel nanodispersed catalysts

The catalytic steam cracking (CSC) of heavy crude oil with high amount of sulfur (4.3 wt %) and high-boiling fractions (>500°C) is studied using Mo and Ni nanodispersed catalysts under static conditions (in an autoclave) at 425°C. Experiments on thermal cracking, steam cracking, and catalytic cracking without water are performed to compare and identify the features of CSC. The relationship between the composition and properties of liquid and gaseous products and process conditions, the type of catalyst, and water is studied. Using Ni catalyst in CSC raises the H: C ratio (1.69) in liquid products, compared to other types of cracking, but also increases the yield of coke and gaseous products, so the yield of liquid products falls. When Mo catalyst is used in CSC, low-viscosity semi-synthetic oil with a higher H: C ratio (1.70) and the lowest amount of sulfur in liquid products (2.8 wt %) is produced. XRF and HRTEM studies of the catalyst-containing solid residue (coke) show that under CSC conditions, nickel is present in the form of well-crystallized nanoparticles of Ni9S8 15–40 nm in size, while molybdenum exists in two phases: MoO2 and MoS2, the ratio between which depends on the conditions of the transformation of heavy crude oil. The findings indicate that CSC is a promising process for improving heavy crude oil.