Heavy Hydrocarbons Research Articles

Influence of group chemical composition of highly viscous oil residues on quality of petroleum road bitumens

The Kalamkas deposit’s oil and its distillation products were studied, and research results on residues and road grade bitumen compositions obtained by oxidation of heavy oil residuest are presented. The atmospheric residue of Kalamkas oil (350 Со) was subjected to vacuum distillation with the selection of gas oil fractions boiling to 380, 400 and 420 Со. Samples of residues were subjected to oxidation in a laboratory installation, which is a batch cube at constant operating conditions. The residues from different depths of gas oil fractions are characterized by different group chemical compositions. The group composition of the residues changes, the content of paraffinnaphthenic hydrocarbons decreases from 29.4 to 23.3% wt. and the proportion of heavy aromatic hydrocarbons increases from 26.8 to 27.8% wt. The content of asphaltenes (from 7.7 to 12.4% wt) and resins (from 17.4 to 22.5% wt) also increases. The ratio of asphaltenes and resins increases from 0.44 to 0.55. With an increase in the depth of selection of gas oil fractions to 420°C, the degree of aromaticity, the ratio of the amount of aromatic hydrocarbons to paraffin-naphthenic ones, increases to 1.79. Road grade bitumens produced from the vacuum distillation residues of Kalamkas oil fuel oil using direct oxidation technology of raw materials have the best performance characteristics if they are obtained from residues boiling in the range of 380–400°C. Residues boiling above 380-400 Со can serve as raw materials for the production of oxidized road bitumen of BND70/100 grade according to ST RK 1373 - 2013.

Effects of Ammonia (NH3) on Flame Characteristics of Methane (CH4) External Premixed Combustion

Methane has long been proposed as an alternative to heavy hydrocarbon fuels due to its low carbon content. However, considering the effect of climate change and the need to transition to zero-carbon, ammonia has recently gained popularity as a sustainable fuel. Nevertheless, previous studies have highlighted the poor combustion of ammonia and the need to blend it with other fuels like methane. As such, this study looks for parameters from the results of the fire of external combustion of premixed methane-ammonia gas. The study was conducted by burning stoichiometry first and then using a volume ratio as the content of the methane-ammonia mixture (ammonia concentration used 0-50%). The gas that comes out of the gas cylinder was adjusted in pressure and flow before mixing and then flowed into the burner to be combusted. The flame propagating from the burner was recorded in a high-speed camera and was used to define the combustion characteristics such as the flame height, flame angle, and dimensionless flame height. The higher concentration of ammonia in the fuel mixture was found to shorten the flame height and dimensionless flame height, while the flame angle became wider.

Indirect effects of oil products on the environment

The article is focused on chemical and radioactive contamination of the environment during hydrocarbon production. The objective of the research is to present relatively unknown facts of indirect long-term environmental effects of hydrocarbon production. Traces of radioactive contamination of soils, ground- and surface water were studied, and also in drinking water in the Republic of Bashkortostan. The authors’ own field and laboratory studies were used. They were performed as part of the preparation of geochemical base map (GHO-1000) of 1:1000000 scale in the Republic of Bashkortostan and in the Ukhto-Izhemsky oil and gas bearing region. The methods applied for laboratory research were inductively coupled plasma mass spectrometry (ICP-MS) for soil and bottom sediment samples and atomic emission spectrometry (ICP-AMS) for ground- and surface waters. It has been determined that in the areas affected by oil production the chemical pollution aspects include deterioration of the groundwater quality caused by associated water and oil products ingress into aquifers due to violation of the oil and gas well drilling techniques, and soil salination caused by frequent equipment breaks during oil production. Aspects of radiation contamination of the environment during oil production include the intake of radionuclides with associated water, and sometimes with heavy hydrocarbon fractions, as well as the consequences of underground nuclear explosions. It is concluded that the territories of hydrocarbon exploration, production and storage should be classified as areas of potential risk for radioactive contamination and chemical pollution (by inorganic compounds, including heavy metal salts). Uranium concentration in drinking water was determined by the INAA method (instrumental neutron activation analysis).

Cobalt nanoparticles confined in silica networks with 3D hierarchical porous features for Fischer-Tropsch synthesis.

Silica network-encapsulated cobalt nanoparticles with an adjustable pore structure as model Fischer-Tropsch synthesis catalysts were successfully prepared. The well-developed shell pore structure of the core-shell catalyst is of great importance for reducing the selectivity of methane, increasing the selectivity of heavy hydrocarbons, and the probability of carbon chain growth. Benefiting from its uniform distribution of cobalt particles and 3D open hierarchical porous shell features, Co@H-mSiO2 catalysts exhibited excellent stability and activity, achieving up to 61.4% selectivity of C5-C20 hydrocarbon products at 6 SL h-1 g-1, 220 °C and 1.0 MPa.

Heavy hydrocarbon recovery with integration of turboexpander and JT valve from highly CO2-containing natural gas for gas transmission pipeline

Demand of natural gas is predicted to increase since many valuable products can be produced. Water and heavy hydrocarbon content are the key for gas pipeline facility. To meet requirement of natural gas transportation, dehydration unit (DHU) and hydrocarbon dew point control unit (DPCU) are necessary to avoid water and hydrocarbon condensation during transmission. The conventional dehydration technology, TEG contactor, can lower water content from 1,304 mg/m3 to 80.35 mg/m3 where the maximum limit of water content in natural gas is 97 mg/m3 to prevent hydrate formation. DPCU is installed to remove heavy hydrocarbon, especially C5+. Integration of JT valve and turboexpander was employed to obtain the low gas dew point. The hot gas stream that entered the JT valve was observed. The lower hot bypass gas was applied, the lower hydrocarbon dew point and the more condensate flowrate was achieved. The highest power generation can be gained at low hot gas flow ratio which also influenced the exit pressure and temperature of compressor. In pipeline simulation, the pressure and temperature drop occurred at the high hot gas rate. To examine the arrival condition, dew point curves were generated and showed that the limitation of hot gas flow ratio has to be below 0.6 to prevent heavy hydrocarbon condensation in pipeline.

A numerical investigation into the stabilization of hydrogen enriched n-dodecane premixed flames

The aviation industry uses heavy hydrocarbon fuels, which release carbon-based emissions upon combustion and could suffer from flame stabilization issues due to their high Lewis numbers at lean conditions. Hydrogen is emerging as an alternative fuel which can help mitigate these issues. A viable strategy is to blend liquid hydrocarbons with hydrogen, which could strengthen the flame in positively stretched regions and help reduce carbon-based emissions. In order to investigate this, we carry out a numerical study for different blends of n-dodecane, which is a surrogate fuel for kerosene and jet fuel, with hydrogen in air. Equivalence ratios and unburnt temperatures of different blends are selected such that the laminar burning velocity remains the same. This condition allows for a more precise characterization of Lewis number effects manifested at the flame base and tip. It is found that up to 60 % addition of H2 into n-dodecane by volume, no major difference is observable with respect to the flame stabilization process. The positively curved flame base burns weakly while the negatively curved flame tip is strengthened due to thermal diffusivity being greater than mass diffusivity. With a further increase in the percentage of hydrogen, the flame base starts to burn stronger with the flame moving closer to the flame holder. However, the flame tip does not become weak as n-dodecane continues to burn there. As positive stretch and negative curvature increase the consumption rate for H2 and n-dodecane flames, respectively, for the blend with 95 % hydrogen and 5 % n-dodecane, a flame is observed with the flame base and the flame tip both burning strong. Overall, this demonstrates that introducing hydrogen at concentrations exceeding 60 % by volume significantly enhances flame stabilization by bringing the flame closer to the flame holder, potentially expanding flame stabilization boundaries.

Geochemical characteristics and genesis of the Ordovician sub-salt natural gas in the Ordos Basin, China

A significant amount of natural gas resources has been discovered in the Ordovician reservoirs under a thick layer of gypsum-salt strata as a result of ongoing research into deep natural gas in China’s Ordos Basin, however, the genetic type and source of the Ordovician sub-salt natural gas remain contentious. These limits understanding how the geochemical properties of the natural gas in Ordos Basin have evolved and how to best guide future exploration and development. Based on the components, carbon and hydrogen isotopic ratios of natural gas from the latest exploration wells, combined with the geological background, this study systematically analyzed the genetic types and sources of sub-salt natural gas of the central and eastern Ordos Basin. The results show that the Ordovician natural gas is mainly composed of hydrocarbon gases with low content of heavy hydrocarbons and dryness (CCH4/CCH4+) above 0.95, belonging to typical dry gas. Non-hydrocarbon gases mainly include N2 and CO2, and some natural gas samples contained H2S. The Ordovician sub-salt natural gas is primarily a self-generating and self-preserving oil-cracking gas with relatively high maturity (Ro ranging from 1.5% to 2.1%) mixed with coal-derived gas generated from upper-Paleozoic coal with relatively low maturity (Ro ranging from 1.1% to 1.5%). Due to the dual-source hydrocarbon supply, the Ordovician sub-salt reservoirs provide favorable gas accumulation conditions and development prospects. This study offers a reasonable explanation for the anomalous geochemical characteristics of the Ordovician sub-salt reservoirs in the Ordos Basin, and also may serve as a guide for future exploration of natural gas in the carbonate gypsum-salt sedimentary system in other basins.

The relationship between site history and human health risks: Lessons from 13 years of contaminated land risk assessments in Victoria, Australia

AbstractSite history is widely recognized as one of the key determinants of the nature and scale of contamination that is likely to be present at a location. While there is vast anecdotal and empirical evidence on the relationship between site history and risk of exposure to pollution, few attempts have been made to systematically collate data across sites to rigorously identify such trends. This study presents an analysis of human health risk metrics extracted from all 1732 contaminated land environmental audits published in Victoria, Australia between 2006 and 2018. The contaminating activities found to be most likely associated with elevated risks to human health were service stations, fuel depots, dry cleaners, gasworks, mechanical parts manufacturers, imported fill and unknown offsite sources generating regional groundwater pollution (usually polluted with trichloroethene). The ten chemical contaminants most frequently assessed in human health risk assessment reports included (in order): benzene, C>10–16 petroleum hydrocarbons, naphthalene, C6–10 petroleum hydrocarbons, xylenes, trichloroethene, toluene, ethylbenzene, benzo(a)pyrene, and tetrachloroethene. The findings of this report include recommendations to develop regulatory guideline values in Australia for trimethylbenzenes, heavy fraction petroleum hydrocarbons (C>16), and trans‐1,2‐dicholoethene, and to strengthen the evidence base informing risks associated with light fraction petroleum hydrocarbons (C6–16) and trichloroethene. To the author's knowledge, this study is the first to extract risk metrics from environmental audit reports and provides a strong evidence base to help regulators, academics and commercial practitioners rank and prioritize sites based on their site history and associated risks.

Numerical study of exhaust chemical composition in a methane DBD plasma actuator under different operating conditions

In this paper, numerical simulations of a Dielectric-Barrier Discharge (DBD) plasma actuator are performed to predict its output chemical composition. The plasma actuator is cylindrical, with two coaxial electrodes and a quartz dielectric. The electrical discharge occurs in a pulsed manner around the quartz wall. This device is utilized for methane conversion in plasma-assisted combustion applications. The effects of voltage, frequency, temperature, and relative permeability parameters on methane conversion and some selected species concentrations were investigated. The results show that plasma discharging converts methane to hydrogen and heavier hydrocarbons such as C2H3, C2H4,C2H5, C2H6, and C3H8. Moreover, increasing the relative permeability coefficient and voltage had the greatest effect on methane conversion. Increasing the relative permeability from 2 to 6 increases the methane conversion by 43 % and also increases the H2 density by 57 %. The conversion rate of methane and the H2 density increase by 18 % with increasing the voltage from 6 to 8 kV. The partial conversion of methane to hydrogen and radical species benefits combustion applications in terms of flame stability and emissions reduction.

Environmental Chemical-Induced Reactive Oxygen Species Generation and Immunotoxicity: A Comprehensive Review.

Significance: Reactive oxygen species (ROS), the reactive oxygen-carrying chemicals moieties, act as pleiotropic signal transducers to maintain various biological processes/functions, including immune response. Increased ROS production leads to oxidative stress, which is implicated in xenobiotic-induced adverse effects. Understanding the immunoregulatory mechanisms and immunotoxicity is of interest to developing therapeutics against xenobiotic insults. Recent Advances: While developmental studies have established the essential roles of ROS in the establishment and proper functioning of the immune system, toxicological studies have demonstrated high ROS generation as one of the potential mechanisms of immunotoxicity induced by environmental chemicals, including heavy metals, pesticides, aromatic hydrocarbons (benzene and derivatives), plastics, and nanoparticles. Mitochondrial electron transport and various signaling components, including NADH oxidase, toll-like receptors (TLRs), NF-κB, JNK, NRF2, p53, and STAT3, are involved in xenobiotic-induced ROS generation and immunotoxicity. Critical Issues: With many studies demonstrating the role of ROS and oxidative stress in xenobiotic-induced immunotoxicity, rigorous and orthogonal approaches are needed to achieve in-depth and precise understanding. The association of xenobiotic-induced immunotoxicity with disease susceptibility and progression needs more data acquisition. Furthermore, the general methodology needs to be possibly replaced with high-throughput precise techniques. Future Directions: The progression of xenobiotic-induced immunotoxicity into disease manifestation is not well documented. Immunotoxicological studies about the combination of xenobiotics, age-related sensitivity, and their involvement in human disease incidence and pathogenesis are warranted. Antioxid. Redox Signal. 40, 691-714.

Identification and quantification of nutrients sources in the Aspio watershed (Italy). Insight from geogenic mineralization and anthropogenic pressure

An accurate evaluation of river water quality could be challenging due to the complex hydrological and anthropogenic processes which affect its nature. Reliable water quality data are mandatory to identify long-term trends and regional variability at the watershed scale. In this study, a combined approach using time series, regression, and multivariate statistical analysis along with SWAT modelling was applied to identify the relevant hydrogeochemical processes and the nutrients sources within the Aspio watershed (Ancona, Italy). The analysis detected different processes: i) the geogenic origin of Cl- and SO42-, ii) the heavy metals (Cu and Ni) and hydrocarbons pollution due to runoff from urban and industrial areas, and iii) the agricultural contribution of pesticides, nitrogen, and phosphorous. A SWAT model was implemented to quantify the nutrients load in the Aspio river. A calibration for streamflow, river sediment yield, and for nutrients load was obtained considering agricultural, urban, and wastewater treatment plant contributions. Agriculture and treated wastewater contributed to the overall nitrogen load only for 4% and 12% respectively, while the majority was due to leakage from urban sewage (84%). A scenario with only fertilizers’ load (excluding other sources) highlighted that nitrogen and phosphorous export from agricultural lands did not significatively impact the Aspio river. The spatial representation of runoff susceptibility also showed how the highest susceptibility for nitrogen and phosphorous loads is due to areas located close to urban settlements.

Determination of the pressure and composition of wet gas fluid inclusions: An in situ Raman spectroscopic approach

Carbonaceous fluid within mineral-hosted inclusions provides important information for carbon cycle in deep Earth. In addition to CH4 and CO2, heavy hydrocarbons (e.g., C2H6 and C3H8) are frequently observed in carbonaceous fluid inclusions (i.e, wet gas inclusions with C1/∑Ci < 0.95). However, determination of the composition of such complex volatiles is difficult based on traditional microthermometric measurements. Here we carried out experimental calibrations on Raman spectroscopic measurements of the pressure (P) and composition of the CH4 ± C2H6 ± C3H8 ± H2S system at room temperature and 0.1–130 MPa. We confirmed that the C–H symmetric stretching vibration band of CH4 [ν1(CH4), ∼2917 cm−1] shifted to lower wavenumber with rising pressure, thus the P-ν1(CH4) relationship could be applied to calculate the pressure of wet gas. It should be noted that the presence of C2+ and/or H2S will shift the [ν1(CH4)] to lower wavenumber at constant pressure (with the order of C3H8 ≥ H2S > C2H6). Obviously, the P-ν1(CH4) relationship derived from pure CH4 system could not be simply applied to wet gas inclusion, otherwise the pressure would be overestimated. To avoid the overlap of the C–H vibrations of CH4, C2H6 and C3H8, the peak areas and peak heights of the overtone vibration of CH4 [2ν4(CH4), ∼2580 cm−1], C–C symmetric stretching vibrations of C2H6 [ν3(C2H6), ∼995 cm−1] and C3H8 [ν8(C3H8), ∼868 cm−1], and S–H symmetric stretching vibration of H2S [ν1(H2S), ∼2612 cm−1] were fitted using Gaussian + Lorentz functions. The obtained peak areas and peak heights were then used to calculate the Raman quantification factors (F factor and G factor, respectively) of C2H6, C3H8 and H2S relative to CH4, respectively. Both the F factor and G factor increased with rising pressure, whereas the FC2H6, FC3H8 and GH2S kept nearly constant at ∼5.69, 6.39 and 153.8, respectively in high pressure gas mixtures (e.g., >30 MPa). Therefore, for inclusions with higher internal pressure, the molar ratio of CH4, C2H6, C3H8 and H2S could be determined by the aforementioned F and G factors. This method was applied to the calcite-hosted single-phase gas inclusions in the Upper Permian Changxing Formation carbonate reservoir from the eastern Sichuan Basin (South China). Our results indicated that the trapping pressure would be obviously overestimated if the presence of heavy hydrocarbons was not taken into account.

Quantifying the Influence of Electrolytes on the Kinetics of Spontaneous Emulsification.

This study quantifies the influence of electrolytes on the kinetics of the spontaneous emulsification phenomenon (SEP) of heavy hydrocarbons in a nonionic surfactant solution. The rate of emulsifying hexadecane in Triton X-100, with the presence of sodium chloride and potassium chloride, has been measured using a technique of monitoring single oil droplet photography. The emulsion droplet size produced in the process was measured under the same conditions by using dynamic light scattering. The data obtained from the two experiments were employed to investigate the mass transfer coefficient of the surfactant molecules through the intermediate layer formed between hexadecane and the surfactant solution. It was found that the electrolytes in an aqueous solution increase the surfactant diffusion rate through the intermediate layer and reduce the emulsion droplet size. As a result, both electrolytes reduce the rate of spontaneous emulsification, with potassium chloride having a more substantial reduction. A model was developed to quantify the influence of electrolytes on the kinetics of the SEP. The data and modeling results verify the influence of ions on the kinetics of spontaneous emulsification. The results provide a significant foundation for predicting the solubilization of heavy hydrocarbons in an electrolyte solution.

Genesis and source of natural gas in Well Mitan-1 of Ordovician Majiagou Formation, middle-eastern Ordos Basin, China

The Well Mitan-1 has achieved a major breakthrough in the exploration of Ordovician subsalt natural gas in the mid-eastern Ordos Basin, demonstrating a high-yield industrial gas flow in fourth member of the Majiagou Formation of Ordovician (O1m4). Despite this success, there are ongoing disputes regarding the origin of the natural gas found in Well Mitan-1. Measured results show that the natural gas in Well Mitan-1 is mainly composed of alkane gas (95.18 %). The gas drying coefficient (C1/C1-5) is measured at 0.947, and the H2S content is 3.49 %, with a small amount of N2 and CO2 in the non-hydrocarbon gas. The carbon isotopic compositions of methane, ethane, and propane in the natural gas are −45.5 ‰, −26.4 ‰, and −24.3 ‰, respectively. Based on the regional geological background, the characteristics of potential source rocks and the geochemical characteristics of natural gas, it is considered that the natural gas in Well Mitan-1 is self-generated and self-accumulated oil-associated gas in Ordovician subsalt carbonate rocks. However, certain geochemical anomalies, such as the lighter methane carbon isotope value (δ13C1) and coal-type gas characteristics in ethane carbon isotope (δ13C2), raise questions. Further insights from thermal simulation experiments on hydrocarbon generation and the analysis of residual gas in rocks suggest a close relationship between the special geochemical characteristics of Well Mitan-1 and the presence of gypsum rocks. The ubiquitous gypsum rock serves a dual purpose: acting as an effective caprock, facilitating the retention of early-generated natural gas, and promoting the generation of heavy hydrocarbon gases (C2+) and H2S. The relatively low H2S content (less than 5 %) and higher C2+ content indicate that thermochemical sulfate reduction (TSR), if present, is not strong enough to significantly impact methane. The δ13C2 is identified as a potentially sensitive parameter for identifying TSR.

Carbon black preparation by partial oxidation of spent tyre pyrolysis oil – Influence of temperature, residence time and oxygen to feed ratio

Preparation of carbon black (CB) by partial oxidation of the spent tyre pyrolysis oil (STPO) and its heavy residue fraction (HRF) was systematically studied using a lab-scale drop tube furnace. The effect of furnace operating temperature (T: 1100 to 1400 °C), residence time (tr: 5 to 60 s) and oxygen to feed ratio (O/F: 174 to 732) on the yield and quality of CB was examined using the response surface methodology (RSM). T was shown to have the most significant influence on CB yield and properties. While the CB yield was also influenced by tr, the quality was more sensitively dependent on T and O/F. The predicted optimal tr and O/F were approximately the same for both feedstocks (60 s and 174, respectively). However, T was higher for the HRF feedstock (1368 °C) than the STPO feedstock (1331 °C) due to the abundance of more viscous heavy hydrocarbons in HRF. Validation experiments under the aforementioned conditions demonstrated the models’ ability to predict responses accurately. The CB from both feedstocks had low contents of ash (<0.03%), volatiles (∼0.5%), sulphur (<0.7%), and high carbon (≥95%). The BET surface area and average primary particle size for CB from STPO and HRF were comparable to those of commercial CBs from fossil fuel feedstock. The CB from HRF had a higher carboxyl oxygen functional group (18%) compared to the CB from STPO (∼13%) and commercial CB (<5%).

Pot experimental trial for assessing the role of different composts on decontamination and reclamation of a polluted soil from an illegal dump site in Southern Italy using Brassica juncea and Sorghum bicolor

A pot experiment was carried out to evaluate the remediation potential of Brassica juncea and Sorghum bicolor in the decontamination of soil polluted with heavy metals such as copper, lead, tin, and zinc along with polychlorinated biphenyls, polycyclic aromatic hydrocarbons, and heavy hydrocarbons. Two composts obtained from different composting processes were tested as biostimulating agents. At the end of the trial, the effect of plant/compost combinations on soil microbial composition, contaminant removal, biochemical indicators, and plant biomass production was determined. The results highlighted that compost addition improved plant biomass despite slowing down plants’ removal of organic and inorganic contaminants. In addition, compost partially enhanced the soil biochemical indicators and modified the relative abundance of the rhizosphere microorganisms. Sorghum showed better mitigation performance than Brassica due to its higher growth. The soil fertility level, the choice of plant species, and microbial richness were found fundamental to perform soil remediation. In contrast, compost was relevant for a higher crop biomass yield.Graphical abstract

Low abundance and high patchiness of decapod fauna sampled with van Veen grab on the West African continental margin (Gulf of Guinea, Ghana)

Sixty morphospecies of Decapoda (Malacostraca: Crustacea) representing 34 families were recorded in the material collected in 2012 from 265 van Veen grab (0.1 m2) samples, from the nine transects distributed along the coast of Ghana in the 25–1000 m depth range. The examined material was dominated by the Diogenidae, Panopeidae, Leucosiidae, Pilumnidae and Xanthidae families. Species accumulation curves showed undersampling of the studied area and a large number of the morphospecies comprised singletons and doubletons. Panopeus africanus was the most frequent morphospecies in the analysed material (9.1% of all samples). We observed a substantial decrease of diversity (Shannon Index) and abundance along a depth gradient. Species richness also decreased with depth, starting from the highest number of morphospecies ‒ 38 at 25 m depth, then 33 at 50 m, 17 at 100 m, 11 at 250 m, 8 at 500 m and ending with 1 morphospecies at 1000 m bottom depth. Higher diversity was observed on the continental shelf (25–250 m – 57 morphospecies), while on the slope (500–1000 m) only eight morphospecies were recorded. Numerous factors of natural and anthropogenic origin may affect decapod communities on the coast of Ghana. Since our material was collected using a sampler collecting material at a very small scale, the observed patterns might be affected by the sampling method.

Applications of Two-Dimensional Laboratory Higher-Frequency NMR in Unconventional Shale Characterization

The complexity of the microstructure and fluids in unconventional reservoirs presents challenges to the traditional approaches to the evaluation of geological formations and petrophysical properties due to the low porosity, ultralow permeability, complex lithology, and fluid composition. Nuclear magnetic resonance (NMR) techniques have been playing major roles in unconventional shale characterization in the last decades as NMR can provide critical information about the reservoirs for quantifying their petrophysical parameters and fluid properties and estimating productivity. Laboratory NMR techniques at higher frequency (HF), e.g., 23 MHz, especially two-dimensional (2D) T1-T2 mapping, and their applications have been essential for the noninvasive characterization of tight rock samples for identifying kerogen, bitumen, heavy or light hydrocarbons, and bound or capillary water. Traditional T2 cutoffs, established with low frequency (LF) NMR, no longer apply and need new definitions to reflect the inferences from water and hydrocarbons separately. The crushed rock analysis method, as applied to unconventional formations, has been successful in evaluating total porosity and water saturation but also suffers from inconsistency in results due to desiccation and solvent effects. In the past decade, the oil and gas industry has witnessed significant development of HF NMR techniques that couple advances in petrophysics, petroleum engineering, and geochemistry with a broad range of applications. It is necessary to review such technological advances and draw conclusions to benefit unconventional core analysis programs. This article will summarize key advances in laboratory NMR applications in unconventional shale characterization, including monitoring processes of liquids equilibrium, desiccation, and imbibition in fresh shale samples, determination of activation energy of hydrocarbons in shales, monitoring changes in a shale sample during liquid flooding experiments, and direct measurements on kerogen.

Enhanced Fischer-Tropsch synthesis performance using graphene Nanosheets-Supported Cobalt-Ruthenium Nanocatalysts: Comparative study with γ-Alumina and carbon nanotubes supports

In this research, graphene Nanosheets (GNS) as Cobalt-Ruthenium Nanocatalysts support have been used in Fischer-Tropsch synthesis. The characterizations of catalysts were evaluated by Fourier-transform infrared spectroscopy (FTIR), Inductively Coupled Plasma (ICP), Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), Energy-dispersive X-ray spectroscopy (EDX), Temperature Programmed Reduction (TPR), and Transmission Electron Microscope (TEM). Afterward, the catalysts' activity, selectivity, and performance were assessed in a fixed-bed reactor at 25 bar. The results were compared by changing the catalyst base to γ-alumina (γ-Al2O3) and carbon nanotubes (CNTs). Measurements were performed in the temperature range of 320––340 °C, the gas ratio (H2/CO) of 2, and the gas hourly space velocity of 3 Lh-1gCat.-1. Using GNS as cobalt catalyst support in Fischer-Tropsch synthesis leads to the 64.5 % and 25.9 % increase in the percentage of CO conversion compared to γ-Al2O3 and CNTs, respectively. Additionally, the utilization of GNS support has resulted in an 11.1 % increase in heavy hydrocarbons selectivity of C5+, in comparison to γ-Al2O3, and a 9.5 % increase compared to CNTs. GNS-based synthesized catalyst with 10 wt% of cobalt and 0.1 wt% of ruthenium (catalyst #6) indicates the highest activity of catalyst at 320 °C with 72.3 % selectivity than heavy hydrocarbons C5+.

Preparation of H-[B]- ZSM -5 zeolites by hydrothermal method as a highly stable and selective catalyst for methanol to propylene (MTP) conversion

A series of high-silica boron-containing H-ZSM-5 zeolites were prepared employing the hydrothermal method. Subsequently, the physico-chemical characteristics of prepared catalysts were comprehensively studied through diverse analytical methods, followed by evaluation of catalytic performance in the methanol-to-propylene (MTP) reaction. The results demonstrated that incorporation of boron into the H-ZSM-5 zeolite induced the reduction in the total surface area and pore volume, accompanied by a raise in the density of weak acid sites. Also, the optimal point for boron content has been recognized at molar coefficient of B2O3/SiO2 = 0.025 for obtaining the highest H-[B]-ZSM-5 performance in MTP process. In comparison to unmodified H-ZSM-5, the optimized H-[B]-ZSM-5 yielded the higher selectivity towards propylene (42.9 % versus 40.1 %) and total light olefins (72.1 % versus 69.5 %), as well as propylene to ethylene ratio (8.1 versus 7.8) with a considerable reduction in selectivity toward C1–C4 alkanes (3.9 % versus 4.2 %) and heavy hydrocarbons (24.1 % versus 26.4 %). Also, the optimized H-[B]-ZSM-5 catalyst exhibited an extended lifetime of 988 h in the MTP process, surpassing the lifetime of unmodified H-ZSM-5 (936 h). These results suggest the optimal point for boron content at B2O3/SiO2 = 0.025 to attain the superior catalytic performance, specifically in terms of propylene yield and catalyst lifetime during MTP process.