Organic Matter Of Oil Shale Research Articles

Biogenic “phosphorus” effect of terrestrial lakes and its significance to oil shale during the Carnian period in the late Triassic

The Triassic lacustrine organic-rich shale (LORS) in Member 7 of the Yanchang Formation (Carnian stage) in the southern Ordos Basin is relatively well developed. Additionally, its organic matter abundance, lake biomass and biodiversity, exceed the maximum values of the other strata deposited during the same period. Apatite is one of the most important minerals and is closely related to biological activities. However, the types and genesis of the continental sedimentary apatite and its significance to shale oil are not clear. Here, the stratigraphy, petrology, and sedimentology of the phosphorus-bearing rock series in the Ma Quan section are studied and its sedimentary environment and phosphorus formation are discussed. The current research shows that apatite in the study area can be divided into three categories: collophanite, bone fossils, and spherical microfossils. These three types of biogenic “phosphorus” products provide effective records of the transformation of the biological substances into sedimentary organic matter. There are two main formation mechanisms: the direct action of organisms and the interaction between the organisms. Bone fossils and spherical microfossils are formed by the direct action of organisms, while collophanite is formed by the indirect action of organisms. The phosphatization methods of the organisms mainly include “coating”, “replacement”, and “filling”, and the presence of a ubiquitous phosphate filler potentially reflects a sufficient phosphate supply. Apatite also is highly important for the development of organic matter in oil shale. First, it changes the productivity conditions. Second, the apatite in the shell of spherical microfossils has a certain protective effect on the organic matter in the inner cavity. In the current study, the geological processes of collophanite deposition and mineralization are explained, an important basis for prospecting phosphate resources is provided, and a new field for the study of the organic matter enrichment mechanism of source rocks is established. At the same time, the process of lake biogenic phosphorus formation provides evidence from the continental deposits in the eastern margin of the Tethys region for exploring deep global changes.

Research on the thermo-hydro-mechanical coupling simulation and deformation spatiotemporal evolution for the entire process of oil shale in-situ mining

The ground surface deformation (GSD) caused by oil shale in-situ mining poses a threat to land resources and human's lives and property. This study, for the first time, conducts a full stratum simulation of the Fuyu oil shale in-situ pyrolysis pilot base, analyzing the evolution characteristics of the temperature field, stress field, and deformation field of the entire stratum profile during the heating and cooling processes of convective heating mining. Considering the changes in the pore structure, thermophysical, and mechanical properties of the stratum, the environmental geological effects of rock deformation during in-situ mining were identified. Simulation results show that after heating, the temperature within 80 cm of the heating well reaches above the initial pyrolysis temperature of 350 °C for oil shale organic matter, and there is a significant stress concentration near the heat source. In the simulation, ground displacement rises in a wave-like manner during heating, quickly subsides after cooling, and finally stabilizes. Eventually, the entire stratum exhibited subsidence, with a subsidence amount of 0.59 cm. The spatiotemporal deformation trend obtained from SBAS-InSAR real-time monitoring results is similar to the simulation results. By comparing the monitoring results with the simulation results, the synergistic deformation mechanism of underground and ground surface co-deformation during in-situ mining of geochemical reactions in the study area was analyzed. The deformation rate is determined by the thermal hysteresis phenomenon and the temperature difference between the heated fluid and the rock layer. This provides scientific support for the geological effect evaluation of oil shale in-situ mining, which helps to improve mining safety and efficiency.

Catalytic Conversion of Oil Shale over Fe or Ni Catalysts under Sub-Critical Water

Sub-critical water is an environment-friendly solvent. It is widely used for the extraction of various organic compounds. It can be used to dissolve and transport organic matter in oil shale. In this study, the conversion of oil shale was synergistically catalyzed by the addition of Fe or Ni to the Fe inherent in samples under sub-critical water conditions. Oil shale can be converted to gas, oil and residues of oil. Thermogravimetric (TG) analysis results presented that the weight loss of raw oil shale was up to 15.85%. After sub-critical water extraction, the weight loss rate of the residues was reduced to 8.41%. With the application of a metal catalyst, Fe or Ni, the weight loss of residues was further reduced to 7.43% and 6.57%, respectively. According to DTG curves, it was found that there were two weight-loss rate peaks. The decomposition process of kerogen in oil shale could be divided into two cracking processes. One is decomposed at a high velocity at around 420 °C, and another is decomposed at a low velocity at around 515 °C. Gas chromatography (GC) results of gas products indicated that Fe or Ni could contribute to producing normal alkanes, such as methane, ethane, propane, etc., which are produced by the hydrogenation of alkenes via hydrogen transfer during the conversion process of kerogen. Gas chromatography-mass spectrometry (GC–MS) was conducted to analyze the components of the liquid products. The results showed that n-alkanes, iso-alkane, oxygenated hydrocarbons and aromatic compounds were the major components of the kerogen cracking products. When Ni was introduced as a catalyst, the contents of aromatic compounds and oxygenated hydrocarbons in the liquid products were increased from 19.55% and 6.87% to 22.38% and 13.77%, respectively. This is due to the synergistic effect of the addition of Ni with the inherent Fe in oil shale under sub-critical water which ensures kerogen is more easily cracked to produce aromatic compounds and oxygenated hydrocarbons.

Insight into low-temperature co-pyrolysis of Qinglongshan lean coal with organic matter in Huadian oil shale

A blend of lean coal (LC) and oil shale organic matter (OSO) was co-pyrolyzed in a fixed bed in the temperature range of 350 °C–500 °C. Changes in specific volatile during the low-temperature co-pyrolysis (LTCP) at a molecular level were analyzed using gas chromatography and pyrolysis-gas chromatography with mass spectrometric detection. In-situ Fourier-transform infrared spectrometry was used to study the real-time changes in active groups during the LTCP. Electron spin resonance was used to reveal radical transfer between LC and OSO. Based on the above characterizations, a microscopic description of synergistic effects regarding product compositions at a molecular level during the LTCP is provided. The results showed that experimental yield for char of the blend was higher than the theoretical value, indicating that one synergistic effect of the co-pyrolysis was to increase the yield of solid product. Infrared spectroscopy and gas chromatography results showed that addition of OSO improved the release of aliphatic compounds, mainly alkanes and alkenes with 7–21 carbons, and CH4 from the lean coal pyrolysis, and inhibited the release of H2 and aromatic compounds with 1–4 rings. OSO has abundant aliphatic compounds that generate sufficient H radicals to stabilize the H-poor radicals produced from coal pyrolysis. The coupling of these two types of radicals, as confirmed by electron spin resonance, accounted for decreases in the yields of H2 and aromatic compounds, and increases in the yields of aliphatic compounds, CH4, and semicoke.

Evolution of organic carbon isotopes during the pyrolysis of Nongan oil shale in Songliao Basin and its implications for in-situ conversion project

Mastering the reaction process of underground pyrolysis is the key to oil shale in-situ conversion project. The progress of the pyrolysis reaction can be analyzed by the information of the kerogen maturity in the reaction formation. However, it is difficult to directly test the kerogen maturity by drilling and coring in in-situ conversion project. And the research on judging the process of underground pyrolysis reaction according to the maturity of oil and gas products has not been carried out in depth. This project intends to take the oil shale of the Nenjiang Formation in the southern Songliao Basin and the pyrolysis oil samples produced by the in-situ conversion project as the research object, and conduct simulation experiments and test analysis. The purpose of this paper is to identify the dynamic evolution characteristics of carbon isotope fractionation during the evolution of oil shale pyrolysis hydrocarbon products, and then establish the response relationship with the process of oil shale organic matter pyrolysis. This study has formed a set of dynamic monitoring methods for the in-situ conversion of oil shale to organic matter pyrolysis reaction process, and laid a theoretical foundation for the efficient, economical and stable operation of oil shale in-situ conversion projects.

THE PATTERNS OF THIOPHENE DERIVATIVES FORMATION IN HIGH-SULPHUR OIL SHALE CRACKING

The composition of cracking products of high-sulphur shale oil from the Kashpir deposit is investigated under different process conditions (duration and temperature). The characteristic features of the influence of heat treatment conditions on changes in the composition of liquid products of oil shale cracking are established. It is shown that the cracking of oil shale organic matter is accompanied by the formation of a wide range of low-molecular sulphur-containing compounds that enter the composition of oils. The changes in the group composition of sulphur-containing compounds of oils have been studied, the features of the distribution of thiophene derivatives, benzo- and dibenzothiophene derivatives in the composition of liquid cracking products are revealed. It is shown that the depth and rate of destruction of sulphur-containing structural fragments of kerogen is significantly affected by the temperature and duration of the process. The data obtained will improve understanding of the patterns of thermal transformations of sulphur-containing structural fragments of organic matter in high-sulphur oil shale during cracking.

Low- and High-Molecular-Weight Oxygen-Containing Compounds of the Organic Matter of Oil Shale from the Dmitrievskoe Deposit (Kuzbass)

Low- and High-Molecular-Weight Oxygen-Containing Compounds of the Organic Matter of Oil Shale from the Dmitrievskoe Deposit (Kuzbass)

Geochemistry of the Tanshan Oil Shale in Jurassic Coal Measures, Western Ordos Basin: Implications for Sedimentary Environment and Organic Matter Accumulation

The Tanshan area is located in the southern section of the west margin of the Ordos basin. The Middle Jurassic Yan’an Formation is relatively thick and rich in coal and oil shale layers, having positive potential for energy development. In order to explore the sedimentary environment of oil shale and the controlling factors of organic matter accumulation, 18 oil shale samples collected from two boreholes (Guyou-3 and Guyou-4) in the Tanshan area were selected as the research objects, and organic geochemical and elemental geochemical tests were carried out systematically. The results show that oil shales have the characteristics of medium oil content, medium ash, high calorific value, low sulfur and low maturity stage, which constitutes good hydrocarbon generation potential. The organic matter is mainly humic type, resulting from terrigenous debris and higher plant debris. The indictors of C-value (mean 81.90), Th/U ratio (mean 3.44), CaO/(MgO·Al2 O3) ratio (mean 0.07), δEu (mean 0.71), δCe (mean 1.15), V/(V + Ni) ratio (mean 0.79), Ceanom index (mean −0.04), Babio index (mean 488.97 μg/g), P/Ti ratio (mean 0.08), TOC/S ratio (mean 59.80), Sr/Ba ratio (mean 0.57) and (La/Yb)N ratio (mean 14.71) indicate that Tanshan oil shales were formed in a warm–humid climate and anoxic-reducing environment, with a low-salinity water body and a low deposition rate but also a relatively low initial paleoproductivity. Paleoclimate conditions, organic matter sources and redox properties of paleowater are the main controlling factors affecting the accumulation of organic matter in oil shales. Although low paleoproductivity and deposition rates are not conducive to the preservation of organic matter, under the conditions of warm and humid climate and a reducing water environment, the continuous and stable input of terrigenous debris and higher plant debris can also cause the enrichment of organic matter.

Pore Structure of Oil Shale Heated by Using Conduction and Microwave Radiation: A Case Study of Oil Shale from the Fushun in China

To examine the evolution of the internal pore structure of and the law of changes in oil shale under different heating modes but at the same temperature, this study subjected φ 20 mm × 20 mm specimens of oil shale to temperatures in the range of 20°C ~500°C by using a muffle furnace and a microwave pyrolysis device. We carried out experiments on the pyrolysis reaction under different temperatures and used scanning electron microscopy, backscattering, the mercury intrusion test, and MATLAB for a refined characterization of the specimens. The results showed that the microwave pyrolysis of oil shale was much shorter than its conduction-induced heating. As the microwave power increased, the time required to reach the target temperature decreased. The phenomenon of “hole blocking” was observed at 400°C ~500°C during conduction-based heating but did not occur in the microwave pyrolysis of oil shale. The porosity of oil shale heated by conduction was 3.4 times higher than its original porosity, whereas that of oil shale heated by microwave radiation was 4.9 times higher than its original value. It can be seen that compared with conduction heating, radiant heating makes the pyrolysis of organic matter in oil shale more complete. During the pyrolysis process of oil shale, the complete reaction of organic matter causes the thermal fracture of the oil shale to produce a large number of pores and interconnected cracks. Thereby, a seepage channel for pyrolysis gas and oil is formed, and the recovery rate of oil and gas is increased.

Structural Characteristics of the Resin–Asphaltene Components of the Organic Matter of Oil Shale from the Dmitrievskoe Deposit and the Liquid Products of Its Conversion in Supercritical Benzene

Structural Characteristics of the Resin–Asphaltene Components of the Organic Matter of Oil Shale from the Dmitrievskoe Deposit and the Liquid Products of Its Conversion in Supercritical Benzene

Coupling of methoxy group with organic matter during methanolysis of heavy hydrocarbon using oil shale as an example

Alcoholysis has been extensively studied for the conversion of heavy hydrocarbons such as coal and biomass, but the roles of alcohols have not been well elucidated. This work aims to investigate the roles of methanol during methanolysis of heavy hydrocarbon with oil shale as an example. It is found that the oil yield of methanolysis is always higher than that of pyrolysis regardless of the reaction temperature but the effect of methanol on the solid product yield is temperature-dependent. At temperatures lower than 290 °C, methanol promotes the oil shale conversion and the solid product yield of methanolysis is lower than that of pyrolysis, which is mainly attributed to the strong supercritical extraction capability of methanol on the oil shale’s pyrolysis products as well as the promoting effect of methanol on reactions of ether oxygen and carboxyl/carbonyl bonds. At temperatures higher than 320 °C, coupling of methoxy moiety in methanol with the organic matter of oil shale and its pyrolysis products as well as the methanol aromatization lead to the formation of oil components such as aromatics, phenols and high boiling point compounds, which result in the increased oil yield. The complex methanol reactions also make methanol become parts of the solid product, leading to a higher solid yield in the methanolysis in comparison with the pyrolysis.

Controlling the in-situ conversion process of oil shale via geochemical methods: A case study on the Fuyu oil shale, China

In order to solve the practical problem that the reaction degree of organic matter cannot be determined in the oil shale in-situ conversion engineering, the evolution law of oil shale pyrolysis products and geochemical parameters that can effectively reflect the transformation of organic matter were studied by indoor simulation experiment in this study. The composition of shale gas produced by pyrolysis shows obvious regular changes and can reflect the various stages of kerogen maturity changes in oil shale. Ro and Tmax in the rock pyrolysis experiment increase with the increase of pyrolysis temperature, which can effectively reflect the maturity of kerogen from immature to mature. Through the study of biomarkers in shale oil products at different pyrolysis temperatures, it is found that the change of biomarkers is regular with the increase of pyrolysis temperature, which can clearly reflect the transformation of organic matter in oil shale from room temperature to 450 °C. This study believes that in the Fuyu oil shale in-situ conversion project in China, the shale oil and gas generated underground is collected from production wells, and then the various maturity parameters of this study are used to estimate the organic matter pyrolysis process of underground oil shale.

The application of Nuclear Magnetic Resonance T1-T2 maps in the research of sedimentary organic matter: A case study of early mature shale with type Ⅰ kerogen

The Nuclear Magnetic Resonance (NMR) 2D T1-T2 map was widely used in shale resources for separation of the different proton contributions, and the obtained data provided lots of information for shale resources evaluation. However, the further work of its application in organic matter quantification and hydrocarbon generation research was quite limited. In this article, we used a low field NMR instrument working at a high frequency (15 MHz) to test isolated organic matter, raw oil shales and shale samples processed by pyrolysis respectively. The results indicated that the kerogen and bitumen could be distinguished by positions located in NMR 2D T1-T2 maps. The standard equations (the relationship between the signal intensity and the mass of isolated organic matter) with excellent linear relationship were established for firstly calculating the content of organic matter in oil shales. The results of NMR were almost identical with that tested by traditional methods. In addition, the NMR relaxometry measurements correlated well with geochemical properties of pyrolyzed oil shales obtained from Rock-Eval pyrolysis (S1 and S2).

A review on co-pyrolysis of coal and oil shale to produce coke

It has become the top priority for coking industry to rationally use and enlarge coking coal resources because of the shortage of the resources. This review focuses on the potential utilization of oil shale (OS) as a feedstock for coal-blending coking, in which the initial and basic step is pyrolysis. However, OS has a high ash content. If such OS is directly used for coal-blending coking, the coke product will not meet market demand. Therefore, this review firstly summarizes separation and beneficiation techniques for organic matter in OS, and provides an overview on coal and OS pyrolysis through several viewpoints (e.g., pyrolysis process, phenomena, and products). Then the exploratory studies on co-pyrolysis of coal with OS, including co-pyrolysis phenomena and process mechanism, are discussed. Finally, co-pyrolysis of different ranks of coals with OS in terms of coal-blending coking, where further research deserves to be performed, is suggested.

Experimental constraints on the evolution of organic matter in oil shales during heating: Implications for enhanced in situ oil recovery from oil shales

In situ oil shale conversion experiments have revealed that to efficiently obtain shale oil, factors such as heating temperature, products, and matter thermal evolution of organic matter during heating need to be optimized. In this study, oil shales from China were subjected to retorting experiments involving eight heating steps. During steps I-II (≤300 °C), the expelled product is mainly water, the hydrocarbon generation potential (PP) of the samples was extremely high, and the organic matter was in the immature to low-mature stage. The oil shale produced a large amount of oil in steps III–VI (300–475 °C), and the TOC contents and S2 of the shale showed the greatest decreases during these steps. The analysis data suggest that the organic matter entered the mature stage during these steps. After heating to 400 °C and expelling a large amount of oil and gas, the PP decreased gradually. From 475 to 520 °C (steps VII–VIII), only a small amount of gas was produced and the organic matter had almost no PP in the high- and over-mature stages. Based on our experimental results, in situ conversion of oil shale the final heating temperature should be ~440 °C. These constraints require further field testing to be properly optimized.

Characterization and thermogravimetric analysis of oil shale from Uvurjargalant deposit

The yield, properties and composition of soluble and insoluble (kerogen) of organic matter of oil shale from Uvurjargalant deposit of Mongolia have been investigated in this study. The study result shows that oil shale contains low amount of moisture and volatile products, while the ash yield is high (71.86 %) - which implies that most of the oil shale are minerals. The total amount of bitumens in the oil shale was very low (1.27 wt %), whereas kerogen content was 22.84 wt %, which is relatively high compared to oil shale from other deposits in Mongolia. Under IR spectral analysis and the ratio of hydrogen and carbon, the Uvurjargalant oil shale belongs to I type of oil shale. The thermogravimetric analysis showed that organic matter of oil shale decomposed at a temperature 300-750 ºC to produce gas and liquid products.

Comparison of Organic Matter from Upper Jurassic Oil Shale of the East European Platform and the Bazhenov Formation by Molecular and Isotopic Data

The molecular and isotopic composition of an extract from the rocks of the Bazhenov Formation in the southeast part of Western Siberia, oils that are genetically related to this formation, and products of hydrous pyrolysis of the organic matter of oil shale (Middle Volgian) of the East European Platform were studied. Common features and differences in their molecular composition were shown. The carbon isotope composition for C14–C30n-alkanes was determined for the first time; a negative isotope anomaly was revealed for C26n-alkane in all samples studied. It was concluded that in spite of the geographical distance, specific biota was revealed in the Volga Basin. This biota conditioned an isotopic indicator, which is genetically significant.

Influence of Temperature on the Hydrogenation of Oil Shale from the Kashpir Deposit

The effect of the hydrogenation temperature of oil shale from the Kashpir deposit on the yield and the properties of the resulting liquid hydrocarbons and gasoline and diesel fractions separated from them was studied. It was found that synthetic oil can be obtained from high-sulfur oil shale with the use of hydrogenation processing. In this case, it is possible to extract more than 90% of the organic matter of oil shale. Depending on the temperature of this processing, the sulfur content of the synthetic oil varied from 2.8 to 4.2 wt %, and the nitrogen and light fraction contents varied from 1.3 to 1.6 and from 34 to 67 wt %, respectively.

Oil shale as a promising source of raw materials for advanced solid fossil fuel technologies

Information on the chemical nature and structure of the organic matter of oil shale from different deposits, the composition and distribution of mineral impurities in the volume of oil shale, and the elemental composition of the organic matter is considered in this article. It was found that the composition and properties of oil shale from different deposits are essentially different, and significant differences can also be observed within the limits of a deposit. Oil shale from some deposits contain trace impurity elements such as uranium, molybdenum, vanadium, and rhenium. In a number of cases, the concentrations of such impurities are increased, and their extraction can be of industrial interest.

Состав растворимого органического вещества горючего сланца богхед (месторождение Таймылырское)

Состав растворимого органического вещества горючего сланца богхед (месторождение Таймылырское)