Search

Due to the multiple influences of unique physicochemical properties of helium, petrographic characteristics and temperature and pressure conditions, little is known about the helium adsorption behaviors in minerals and rocks at geological conditions. Based on the grand canonical Monte Carlo simulations, this study revealed the adsorption characteristics of pure helium and the competitive adsorption of binary mixtures with different proportions of methane and helium under geological temperature and pressure conditions in quartz slit model. Molecular simulation of pure helium shows that physical adsorption of helium exists in mineral surfaces, which indicates a preservation mechanism of helium in helium source rocks. Binary mixtures simulations indicate that the adsorption capacity of methane in quartz is stronger than that of helium, and the competitive adsorption of methane increases with decreasing burial depth. This means that during the upwards migration processes of natural gas, the adsorbed helium that distributed in the migration pathway will be gradually displaced by methane, then concentrate in the hydrocarbon gases and subsequently accumulate together in favorable traps to form helium-rich natural gas reservoirs. Our results provide a molecular-scale insight into the preservation and accumulation of helium in helium source rocks and are significant for assessing the helium resource potential. [ABSTRACT FROM AUTHOR]

Iron homeostasis plays an essential role in joint health, while iron overload can cause damage and death of cartilage cells. Cardamonin (CAR) is a substance found in the fruit of the chasteberry plant and has anti-inflammatory and anti-tumor activities. We first administered iron dextran (500 mg/kg) intraperitoneally to establish an iron overload mouse model and surgically induced osteoarthritis. The extent of OA and iron deposition were assessed using Micro-ct, Safranin-O/fast green staining, H&E staining, and Prussian Blue 10 weeks later. We administered primary chondrocytes with Ferric Ammonium Citrate (FAC) to evaluate the chondrocyte changes. Chondrocytes were identified in vitro by toluidine blue staining, and chondrocyte viability was evaluated by CCK-8. The rate of apoptosis was determined by Annexin V-FITC/PI assay. The mechanism of action of CAR was verified by adding the SIRT1 inhibitor EX527, and the expression of SIRT1 and MAPK signaling pathways was detected by Western blot. Iron overload also promoted chondrocyte apoptosis, a process that was reversed by CAR. In addition, CAR reduced NLRP3 inflammasome production via the SIRT1-MAPK pathway, and the SIRT1 inhibitor EX527 inhibited the treatment of OA by CAR.CAR inhibited cartilage degeneration induced by iron overload both in vivo and in vitro. Besides, our study showed that iron overload not only inhibited type II collagen expression but also induced MMP expression by catalyzing the generation of NLRP3 inflammasome. Our results suggest that CAR can treat KOA by promoting SIRT1 expression and inhibiting p38MAPK pathway expression to reduce the production of NLRP3 inflammasome vesicles. [ABSTRACT FROM AUTHOR]

The identification of the origin and source of natural gas is always a difficult and hot issue. Hereinto, the maturity identification is one of the most important scientific problems. Many empirical equations have been established to decipher the relationship between the maturity of gas source rocks and the carbon isotopic composition of natural gas. However, these equations proposed often fail to identify the maturity of the source rocks correctly, which in turn prevents the identification of genetic types and source rocks of the natural gas because the petroliferous sedimentary basins in China are complex and diverse, with multiple sets of source rocks and different thermal history. In this paper, the oil-associated gas from the Permian lacustrine source rocks and the coal-derived gas from the Jurassic source rocks in Junggar and Turpan-Hami basins have been investigated to decipher the relationship between the maturity (vitrinite reflectance) of gas source rocks and the carbon isotopic composition of methane. The equations established are δ13C1=25lgRo−42.5 for oil-associated gas, and δ13C1=25lgRo−37.5 for coal-derived gas. These new equations are suitable for the maturity identification of source rocks in most petroliferous basins, and favorable for the identification of the genetic type and source of natural gas, which is very important to improve the geological theory of natural gas. [ABSTRACT FROM AUTHOR]

A three-dimensional (3D) fluorine-doped graphene aerogel (FGA) with rich semi-ionic C–F bonds was synthesized via a facile hydrothermal method and applied as the electrode material in supercapacitor. A porous 3D network structure with a high specific surface area of the FGA has been confirmed by the combination of scanning electron microscopy, transmission electron microscopy and N2 adsorption method. X-ray photoelectron spectroscopy spectra indicated that the FGA was doped predominantly with semi-ionic C–F bonds, which ensured the high electronic conductivity and sufficient electrochemistry active sites of FGA. As a result, the FGA electrode showed a high specific capacity of 279.8 F g−1 at a current density of 0.5 A g−1, which is much better than that of undoped graphene aerogel (UGA, 141.6 F g−1). Even though the current density increased to 10 A g−1, 90.6% of its specific capacitance was retained. The FGA also maintained about 94.3% of the initial capacitance after 5000 cycles at a current density of 0.5 A g−1. Furthermore, the assembled FGA//FGA symmetric supercapacitor presented a high energy density of 26.2 W h kg−1 at a power density of 899 W kg−1. Accordingly, this work offers a facile and efficient approach to produce fluorine-doped graphene materials for high-performance supercapacitor applications. [ABSTRACT FROM AUTHOR]

Hydrocarbon migration mechanism in deep Ordovician reservoir of the Halahatang area, Tarim Basin, is investigated based on the analysis of the geological setting and geochemical parameters. The parameters successfully analyzed include oil–gas properties, crude oil maturity [Ts/(Ts + Tm) ratio], gas carbon isotopic ratios, and trace elements (B, V, Ni, and Cu) in crude oil. The results show that hydrocarbons migrate into the Ordovician of the Halahatang area from the Manjiaer Depression and the Halahatang area itself through unconformities and faults. The overall hydrocarbon migration orientation in the area is generally from south to north. The oil and gas migration process determine parameters vary regularly from south to north as follows: oil density, V/Ni ratio, Ni/Cu ratio, and concentrations of V, Ni and (Ni + B) in crude oil regularly increase, whereas Ts/(Ts + Tm), gas/oil ratio, and dryness coefficient gradually decrease, and methane show a trend toward depletion of heavy carbon isotopes. Additionally, there exist obvious anomalies of geochemical parameter values in the Repu3 well block, which indicates that a local fault intersection could provide a favorable hydrocarbon filling point. Based on these findings, further exploration activities in the deep Ordovician reservoir of the Halahatang area should be conducted in the southern part of the Halahatang area along the oil charging pathways, and fault intersection zones should be emphasized. [ABSTRACT FROM AUTHOR]

There is emerging interest in the anaerobic degradation of crude oil. However, there is limited knowledge about the geochemical effects and microbiological activities for it. A mixture of anaerobic sludge and the production water from an oil well was used as an inoculum to construct four consortia, which were incubated under sulfate-reducing or methanogenic conditions at either mesophilic or thermophilic temperatures. Significant degradation of saturated and aromatic hydrocarbons and the changing quantities of some marker compounds, such as pristane, phytane, hopane and norhopane, and their relative quantities, suggested the activity of microorganisms in the consortia. Notably, the redox conditions and temperature strongly affected the diversity and structure of the enriched microbial communities and the oil degradation. Although some specific biomarker showed larger change under methanogenic condition, the degradation efficiencies for total aromatic and saturated hydrocarbon were higher under sulfate-reducing condition. After the 540-day incubation, bacteria of unknown classifications were dominant in the thermophilic methanogenic consortia, whereas Clostridium dominated the mesophilic methanogenic consortia. With the exception of the dominant phylotypes that were shared with the methanogenic consortia, the sulfate-reducing consortia were predominantly composed of Thermotogae, Deltaproteobacteria, Spirochaeta, and Synergistetes phyla. In conclusion, results in this study demonstrated that the different groups of degraders were responsible for degradation in the four constructed crude oil degrading consortia and consequently led to the existence of different amount of marker compounds under these distinct conditions. There might be distinct metabolic mechanism for degrading crude oil under sulfate-reducing and methanogenic conditions. [ABSTRACT FROM AUTHOR]

With wells Puguang 2 and 6 in the Puguang gas field as the research objects by choosing organic carbon as characterization reservoir carbon (indirectly reflecting the bitumen contents), this paper discusses the relationship between bitumen contents and lithologic characteristics, reservoir characteristics, and calculates the volume of paleooil and oil cracked gas. The study shows that the organic carbon contents of the reservoirs are related to lithologic characteristics. Due to variations in the particle size or structure of rocks, the porosity of the reservoirs varies, furthermore, it will influence the contents of organic carbon. And the relationship between these two parameters is positive. Based on the analysis, the relationship between total organic carbon (TOC) and the contents of reservoir bitumen also appears to be positive. The volume of paleo-oil and cracked gas of the Changxing-Feixian'guan Formation are respectively 495 million tons and 360.4 billion m through the calculation of reservoir's organic carbon. Therefore, the relationship between carbon-bearing rate and characteristics of the reservoirs can be used to indirectly evaluate reservoir types. Besides, the carbon-bearing rate of the reservoirs also reflects the contents of reservoir bitumen, paleo-oil as well as natural gas. It makes a new approach for the study of the types of reservoirs and the amounts of paleo-oil and oil cracked gas in northeastern Sichuan Basin. [ABSTRACT FROM AUTHOR]

Based on gas chromatography and gas chromatography mass spectrometry techniques, the authors examined biomarker characteristics of the Ganquan Formation source rocks in the area of Dahulishan, Ejina, and analyzed the information and petroleum geological significance that were indicated by the source of organic matter, sedimentary environment and maturity and so on. Gas chromatography peak of saturated hydrocarbons from the Ganquan Formation source rocks showed “the former peak” of the single peak distribution, the main peak of carbon being C 18, indicating the main sources of organic matter with marine organic matter. Pr/Ph ranges from 0.3 to 0.6, indicating a strongly reducing sedimentary environment. Biomarker assemblages of the Ganquan Formation source rocks are abundant in tricyclic terpane with long side chains, with a high level of gammacerane, showing dominant distribution of C 27 sterane. High contents of gammacerane in organic matter show organic facies of source rocks in the saltwater sedimentary environment. That average hopane/sterane ratio is 0.59, showing that algae have made more contributions to organic matter than bacteria. And the high level of C 27 steranes shows that algae are the main source of hydrocarbon precursors. The Ganquan Formation’s methylphenanthrene index, which is an effective molecular parameter index to measure thermal evolution of organic matter, ranges from 0.35 to 0.50, and the conversion of vitrinite reflectance Rc from it is within the range of 2.00–2.09, indicating that the Ganquan Formation source rocks are in the over-mature stage of thermal evolution. [ABSTRACT FROM AUTHOR]

Natural gas pools with the high contents of CO were discovered during exploring the middle fault zone of the Hailar-Tamtsag Basin. So far this kind of gas reservoir with CO with characteristics of carbon isotope is special. The stable carbon isotope of CO in the study area is relatively light with δ $$C_{CO_2 }$$ values ranging from −13.1‰ to −8.2‰. The Ar/Ar values of associated argon gas range from 916 to 996, with R/Ra of 1.20-1.26. Based on comprehensive analysis, it is believed that the CO gas in this study area is of crust mantle source. [ABSTRACT FROM AUTHOR]

In the Tarim Basin, black shale series at the bottom of Cambrian is one of the important marine facies hydrocarbon source rocks. This research focuses on the analysis of the isotope of noble gas of 11 cherts. The R/ Ra ratio of chert in the Keping area is 0.032–0.319, and 40Ar/36Ar is 338–430. In Quruqtagh the R/ Ra ratio is 0.44–10.21, and 40Ar/36Ar is 360–765. The R/ Ra ratio of chert increases with 40Ar/36Ar from the west to the east accordingly. They have evolved from the crust source area to the mantle source area in a direct proportion. Surplus argon 40ArE in chert is in direct proportion to the R/ Ra ratio, indicating that it has the same origin of excess argon as in fluid and mantle source helium. Comparison of the R/ Ra ratios between the west and the east shows that the chert in the eastern part formed from the activity system of the bottom hydrothermal venting driven by the mantle source, where the material and energy of crust and mantle had a strong interaction in exchange; whereas in the western part, chert deposited from the floating of hydrothermal plume undersea bottom, which is far away from the centre of activities of the hydrothermal fluid of ocean bottom. In addition, from noble gas isotope composition of chert, it is suggested that the ocean anoxia incident happened at the black shale of the Cambrian bottom probably because of the large-scaled ocean volcanoes and the following hydrothermal activities. [ABSTRACT FROM AUTHOR]

A suit of oil shales, predominated by black argillaceous silicalite and finely laminated black-brown shale, has been discovered in a set of carbonaceous-siliceous mudstone formations (350 m in thickness) in the third member of Xiamaling Formation of the Upper Proterozoic Qingbaikou Series (900-873 MaBP), Xiahuayuan, Hebei Province, China. The oil shale, combustible with strong bitumen odour, has super-high TOC contents ranging from 21.4% to 22.9%, bitumen “A” contents from 0.58% to 0.88% and oil length from 5.29% to 10.57%. The ultrathin section observation of the shale and the identification of its kerogen demonstrate that its hydrocarbon-generative parent material is mainly benthonic Rhodophyta whose specific tetrasporangia are legible and abundant. It is rarely reported in the literature that such a hydrocarbon-generative parent material, composed mainly of Rhodophyta and with extraordinarily high contents of TOC and bitumen “A”, developed into a set of high-quality source rocks. The extracts of the oil shale are characteristic of richness in 17α(H)-diahopanes and n-alkyl tricyclic terpenoids but low in steranes. Such a biomarker feature is obviously different from that of the extracts from other Proterozoic marine carbonate source rocks of the studied area. Since the biological constitution of this oil shale is rather simple, it is clear that these biomarkers most likely represent to certain extent the specific molecular constitutions of the benthonic Rhodophyta identified in the ultrathin sections of the samples. Studies on its lithologic association and depositional sequences suggest that this suit of the carbonaceous-siliceous mudstone formation, which contains oil shales, was probably developed in an undercompensation deep-bay environment when a maximum transgression occurred during the formation of the third member of Xiamaling Formation. The high concentration of SiO2 in this organic-rich rock and the positive correlation between TOC and some trace elements such as P, Cu, Ni, W and Mo indicate that this suit of rocks was affected by activities of bottom thermal currents as deposited. [ABSTRACT FROM AUTHOR]

This study analyzed the developing environments of hydrocarbon source rocks in the Ordos Basin and evaluated carbonate rocks as hydrocarbon source rocks and their distributions on account of the fact that China’s marine carbonate rocks as hydrocarbon source rocks are characterized by the intensive thermal evolution and relatively low abundance of organic matter, by taking the Lower Paleozoic of the Ordos Basin for example and in light of the calculated enrichment coefficients of trace elements, the profile analysis of trace element contents, ratios of relevant elements, and stable isotopic compositions and their three-dimensional diagrammatization in combination with the necessary organic parameters. As for the Ordos Basin, TOC=0.2% is an important boundary value. Studies have shown that in the strata TOC>0.2%, V/(V+Ni)>0.50, Zr/Rb<2, Rb/K(× 104)>30, Z<122, Th/U>0.80, Zn and Mo are enriched with a positive δ13Ccarb excursion. All these indicated a stagnant and stratified sedimentary environment that has low energy, anoxia and high salinity in bottom water. In these strata the geological conditions are good for the preservation of organic matter, hence favoring the development of hydrocarbon source rocks. These strata have δ13Corg <−28‰ (I–II type) and high hydrocarbon-generated potential. The Klimory and Wulalik formations show certain regularities in those aspects, therefore, they can be regarded as the potential effective hydrocarbon source rocks. In the strata TOC⩽0.2%, Zr/Rb>1, V/(V+Ni)<0.50, Rb/K<30, Th/U<0.80, Cu, Zn, etc are depleted, and δ13Corg values range from −24‰ to −28‰. All these facts showed that most of the carbonate rocks or mudstones were formed in high-energy oxidizing environments, thus unfavorable to the development of hydrocarbon source rocks. It is feasible to make use of the geochemical method to comprehensively assess the highly evolved marine carbonates rocks as potential hydrocarbon source rocks and their distributions. [ABSTRACT FROM AUTHOR]

This study reversed the developing environments of hydrocarbon-source rocks in the Ordos Basin and evaluated carbonate rocks as hydrocarbon-source rocks and their distributions on account of the fact that China’s marine carbonate rocks as hydrocarbon-source rocks are characterized by intensive thermal evolution and relatively low abundance of organic matter, by taking the Lower Paleozoic of the Ordos Basin for example and in light of the calculated enrichment coefficients of trace elements, the REE distribution patterns, the mathematical statistics analysis of elements and carbon isotopes and their three-dimensional diagrammatization in combination with the necessary organic parameters. As for the Ordos Basin, TOC=0.2% is an important boundary value. Studies have shown that in the strata where TOC is greater than 0.2%, Ba is highly enriched with positive δ13Ccarb shifts and δ13Corg less than −28‰, reflecting a thigh paleo-productivity, high burial amounts of organic matter, relatively good hydrocarbon-generating potentiality and intensive REE fractionation. All these indicated that the settlement rates are low and the geological conditions are good for the preservation of organic matter, hence favoring the development of hydrocarbon-source rocks. The Klimory and Wulalik formations show certain regularities in those aspects and, therefore, they can be regarded as the potential effective hydrocarbon-source rocks. In the strata where total TOC is less than 0.2%, the contents of Ba are low, δ13Ccarb values are mostly negative, and δ13Corg values range from −24‰–−28‰, demonstrating low burial amounts of organic matter, poor potentialities of hydrocarbon generation, weak REE fractionation and rapid settlement rates. These facts showed that most of the hydrocarbon-source rocks were formed in shallow-water, high-energy oxidizing environments, thus unfavoring the development of hydrocarbon-source rocks. It is feasible to make use of the geochemical method to comprehensively assess the highly evolved marine carbonates rocks as potential hydrocarbon-source rocks and their distributions. [ABSTRACT FROM AUTHOR]

Study indicates that the elements rich in marine floor hydrothermal fluids have a positive influence, not only on total organic carbon (TOC), but also on the abundance of SiO2 in some Middle-Upper Proterozoic strata. The TOC bears a better positive correlation with abundance of SiO2. By the correlation analysis between organic matter and sea-floor hot fluid characterized trace elements such as P, Cu, Zn, Ni, Ba, etc in marine carbonate rocks, we conclude that organic matter enrichment of carbonate rocks were related to marine floor hydrothermal activity in a part of layers. Some thin-layered cherts, which were thought to be the indicators of hydrothermal activity, frequently occurring in Gaoyuzhuang, Wumishan, Tieling and Xiamaling formation support our conclusion. With the increasing of trace elements in marine carbonate rocks, the TOC and Fe/Ti ratio is creasing. In contrast, the Al/(Al+Fe+Mn) ratio is usually decreasing. [ABSTRACT FROM AUTHOR]

This study presents an overview on the geological setting and geochemical characteristics of Pleistocene shallow gas accumulations in eastern Qaidam Basin, NW China. Five largest gas accumulations discovered in this region have a combined enclosure area of about 87 km² and 7.9 trillion cubic feet (tcf) of proven plus controlled gas reserves. The dominance of methane (>99.9%) and the δ 13C and δD values of methane (-68.51‰ to - 65.00‰ and - 227.55‰ to - 221.94‰, respectively) suggest that these gases are biogenic, derived from the degradation of sedimentary organic matter by methanogens under relatively low temperatures (< 75°C). A sufficient supply and adequate preservation of organic matter in the Pleistocene sediments is made possible by the lake basin's high altitude (2600 -3000 m) , high water salinity (> 15%) and strong stratification. The deposition and extensive lateral occurrence of shore and shallow lake sands/silts in beach sand sheets and small sand bars provided excellent reservoirs for the biogenic gas generated from adjacent rocks. Effective but dynamic gas seals were provided by such factors as intermittent vertical variations in the sediment lithologies, hydraulic trapping due to mudstone water saturation, the hydrocarbon gradient created as a result of gas generation from potential caprocks, and the presence of a regional caprock consisting of 400 - 800-m-thick mudstones and evaporites. It appears that the most favorable traps for large gas accumulations occur on structural slopes near the major gas kitchen, and the prolific gas pools are often those large gentle anticlines with little faulting complication. [ABSTRACT FROM AUTHOR]

Focuses on a study which uses the biogenic theory to investigate the properties of natural gas. Indepth look at the theoretical basis of abiogenic natural gas; Information on the geochemical characteristics and differentiations of abiogenic natural gas; Detailed information on research which was conducted on a abiogenic gas reservoir in the Songliao Basin.