Search

Based on the situation and progress of marine oil/gas exploration in the Sichuan Basin, SW China, the whole petroleum system is divided for marine carbonate rocks of the basin according to the combinations of hydrocarbon accumulation elements, especially the source rock. The hydrocarbon accumulation characteristics of each whole petroleum system are analyzed, the patterns of integrated conventional and unconventional hydrocarbon accumulation are summarized, and the favorable exploration targets are proposed. Under the control of multiple extensional-convergent tectonic cycles, the marine carbonate rocks of the Sichuan Basin contain three sets of regional source rocks and three sets of regional cap rocks, and can be divided into the Cambrian, Silurian and Permian whole petroleum systems. These whole petroleum systems present mainly independent hydrocarbon accumulation, containing natural gas of affinity individually. Locally, large fault zones run through multiple whole petroleum systems, forming a fault-controlled complex whole petroleum system. The hydrocarbon accumulation sequence of continental shelf facies shale gas accumulation, marginal platform facies-controlled gas reservoirs, and intra-platform fault- and facies-controlled gas reservoirs is common in the whole petroleum system, with a stereoscopic accumulation and orderly distribution pattern. High-quality source rock is fundamental to the formation of large gas fields, and natural gas in a whole petroleum system is generally enriched near and within the source rocks. The development and maintenance of large-scale reservoirs are essential for natural gas enrichment, multiple sources, oil and gas transformation, and dynamic adjustment are the characteristics of marine petroleum accumulation, and good preservation conditions are critical to natural gas accumulation. Large-scale marginal-platform reef-bank facies zones, deep shale gas, and large-scale lithological complexes related to source-connected faults are future marine hydrocarbon exploration targets in the Sichuan Basin.

Despite over 60 years of helium development in the Sichuan Basin, the mechanism of helium enrichment remains poorly understood. Helium-rich gas is primarily found as gas composition analysis in the fields. This study explores the relationship between helium distribution and two regional shale formations (the Qiongzhusi and Wufeng-Longmaxi formation), basing on the spatial distribution of these shales, structural profiles, and reported helium concentrations. Our findings indicate a typical trend of helium enrichment within the Sichuan Basin, where helium concentrations generally increase from the basin margins toward its center. The R/Ra ratios in the natural gas are consistently below 0.1, indicating that the helium mainly originates from the granite basement. The Wufeng-Longmaxi Formation is absent from central to western parts of this basin. The hydrocarbon generation intensity of this shale is 3,627.26 m³/m2, which is 25,896.7 times greater than its helium generation intensity (0.14 m³/m2). Its helium capture time is short (237 Ma). There is no obvious correlation between the distribution of helium concentration and Wufeng-Longmaxi shale. The Qiongzhusi shale extends across the entire Sichuan Basin. Its hydrocarbon generation intensity is approximately 57 m³/m2, which is 267.4 times greater than its helium generation intensity (0.27 m³/m2). Beneath this shale, the Pre-Sinian granite exhibits a helium generation intensity exceeding 0.51 m³/m2, acting as the primary helium source rock in the basin. The helium capture time of Qiongzhusi shale is 435 Ma. Helium concentration increases as the burial depth of the Qiongzhusi shale decreases, and helium becomes isotopically lighter in the direction of fluid potential drop. This indicates that helium enrichment in the Sichuan Basin is predominantly influenced by the Qiongzhusi shale. From maximum burial depth to present, helium solubility in water has decreased by approximately 63.6% and 54.3% in the Wufeng-Longmaxi and Qiongzhusi shale respectively, suggesting that uplift processes contributed to helium degassing into gas reservoirs. The regional shale influenced the long-distance migration of helium, although faults can alter this pathway. Faults may either promote helium accumulation in shallow gas fields, such as the Jinqiu gas field, or lead to helium loss, as observed in the southeastern region of the Sichuan Basin.

The poor dispersion stability and susceptibility to oxidation significantly restrict the practical application of MoS2 as a lubricant additive. Here, MoS2 nanocomposite powders with magnesium silicate hydroxide (MSH) reinforcement and amorphous carbon protection were prepared via a straightforward two-step procedure. Detailed studies of the structure, phase composition, tribological properties, and lubrication mechanism of the composite powder have been conducted. The results demonstrated that the morphology of the composite powders was rod-shaped MSH coated with amorphous carbon and layered MoS2. The introduction of amorphous carbon into the MSH/MoS2 composite powders results in enhanced dispersion and a reduction in corrosion to copper sheets. Furthermore, the addition of 1.0 wt% MSH/MoS2/C nanoparticles to PAO-6 led to a decrease in the COF of the lubricating oil from 0.104 to 0.063. Meanwhile, the wear rate of the friction pair decreased from 5.91 × 10−7 mm3 N−1 m−1 to 2.22 × 10−7 mm3 N−1 m−1. The excellent performance could be attributed to the introduction of amorphous carbon effectively prevents the oxidation of MoS2 within the additive, leading to improved friction and wear resistance. The tribo-film, composed of MSH, Fe2O3, FeS, MoS2, graphite, and amorphous carbon, demonstrates remarkable capabilities in reducing friction and wear.

Abstract In this study, detrital zircon U–Pb geochronology, trace element and Hf isotopic compositional data from the Early-Middle Triassic clastic rocks in the eastern Sichuan Basin were obtained to distinguish the sediment provenance and constrain the timing of the initial collision between the South China and North China blocks. Detrital zircons from the Early Triassic Feixianguan Formation clastic rocks yield one major age peak at 2476 Ma and three minor age peaks at 1886, 802 and 304 Ma. These detrital zircons may be derived from the South China Block. Detrital zircons from the Early Triassic Jialingjiang Formation clastic rocks yield multiple age peaks at 979, 856, 392 and 269 Ma, indicating a mixed sediment provenance from the South China Block and Qinling Orogenic Belt. This is the first appearance of the detritus with the Qinling Orogenic Belt affinity in the eastern Sichuan Basin. Detrital zircons from the Middle Triassic Leikoupo Formation clastic rocks yield two centralized age peaks at 447 and ca. 245 Ma. These zircons may mainly be derived from the Qinling Orogenic Belt. The results indicate an abrupt change in the detrital zircon U–Pb provenance from the South China Block to the Qinling Orogenic Belt during the Early-Middle Triassic. Integrating the provenance change and other geological characteristics, we suggest that the initial collision in the eastern Qinling Orogenic Belt occurred in the Early Triassic.

LaB6/TiC/TiB was incorporated into a Ti–Al–Zr–Sn alloy to achieve an efficient improvement in acid-resistance. The incorporation of LaB6/TiC/TiB deteriorated the performance of the passive layer, but impeded the penetration of the corrosive medium into Ti matrix. The incorporation of the conductive reinforcements promoted galvanic corrosion, leading to a decrease in barrier effect of the passive film. Delayed passivation in less aggressive media was achieved by controlling the formation and growth of corrosion pits. The distribution of LaB6/TiC/TiB determined the corrosion properties after complete failure of the passive layer. An appropriate approach for enhancing the acid-resistance of Ti-based materials was suggested.

Diagenesis has been demonstrated to significantly affect porosity development in shale reservoirs, however, the effect of diagenetic modifications on shale pore structures is still unclear. For clarifying this issue, this paper focuses on the Upper Ordovician to Lower Silurian Wufeng and Longmaxi shales, which are the only commercially gas-produced shale plays in China. This study aims to reveal the influence of diagenetic alterations on the WF-LMX shale reservoir quality by integrating total organic carbon (TOC) content, X-ray diffraction (XRD), low-temperature gas (N2) and carbon dioxide (CO2) adsorption experiments, field-emission scanning electron microscopy (FE-SEM), energy dispersive X-ray (EDS), and cathodoluminescence (CL) analyses. Three major shale lithofacies were identified, mainly including siliceous, siliceous–argillaceous mixed, and argillaceous shale; the siliceous shale has a relatively high TOC content. The organic pores, intergranular pores, intragranular pores, and fractures are generally developed in the WF-LMX shales. The pore volume (PV) and specific surface area (SSA) of micropores, mesopores, and macropores of siliceous shales are higher than those of mixed shales and argillaceous shales. The TOC content has a strongly positive correlation with PV and SSA for micropores and mesopores. After combustion, the PV and SSA of micropores and mesopores were decreased, whereas the PV and SSA of macropore were significantly increased. In the siliceous shale, organic pore is the dominant pore type due to the fact that a large amount of authigenic microcrystalline quartz aggregates can protect organic pores from compaction. The argillaceous shale has high clay and low TOC content, and the dominant pore type is pores between clay flakes. The siliceous shale has a relatively high TOC content, large PV and SSA, and so are the dessert lithofacies for shale gas exploration.

To improve the content of extracellular polysaccharide (EPS) in fermented blueberry juice, three strains of lactic acid bacteria with high EPS production were selected in this study, and the fermentation conditions of blueberry juice were optimized by single-factor method and response surface methodology (RSM), and the four most influential factors were screened out, namely, initial pH, inoculum amount, fermentation temperature and fermentation time. Based on this, the optimal fermentation process conditions were obtained by artificial neural network (ANN) and genetic algorithm (GA). The optimized process conditions were 2:1:1 ratio of Lactobacillus plantarum 9sh, Lactobacillus fermentum SR2-6 and Citrobacter cepacia GM11, lactose was 6%, soybean peptide was 0.6%, the initial pH of blueberry juice was 4.5, the inoculum amount was 8%, fermentation temperature was 30 ℃, and fermentation time was 60 h. Under these conditions, the EPS content was 3.537 g/L. This study shows that RSM and ANN can be used to optimize the EPS production process of blueberry juice by lactic acid bacteria fermentation.

The self-lubricating ceramic coatings that can control friction and wear have attracted researchers’ widespread attention. However, the poor interfacial bonding between lubricants and ceramics and the deterioration of mechanical properties due to a tribological design limit their practical applications. Here, a robust self-lubricating coating was fabricated by an in-situ synthesis of MoS2/C within inherent defects of thermally sprayed yttria-stabilized zirconia (YSZ) coatings. The edge-pinning by noncoherent endows hybrid coatings with excellent interfacial strength, increasing their hardness (HV) and cohesive strength. Furthermore, owing to the formation of a well-covered robust lubricating film at a frictional interface, a coefficient of friction (COF) can be reduced by 79.6% to 0.15, and a specific wear rate (W) drops from 1.36×10−3 to 6.27×10−7 mm3·N−1·m−1. Combining outstanding mechanical properties and tribological performance, the hybrid coating exhibits great application potential in controlling friction and wear. Importantly, this strategy of introducing the target materials into the inherent defects of the raw materials to improve the relevant properties opens new avenues for the design and preparation of composite materials.

Introduction: Biomimetic lubricant-infused porous surfaces are developed and applied for omniphobicity and corrosion protection, which exhibit great advantages compared to superhydrophobic surfaces.Methods: Herein, superhydrophobic Fe@E-Zn@PFOA was prepared via the electrodeposition of laminated Zinc coating, further vapor etching, and post-modification with perfluoro caprylic acid. The facile, inexpensive, and environment-friendly water vapor etching process can form a porous honeycomb-like structure. Moreover, the perfluoropolyether lubricant was wicked into the porous and superhydrophobic surfaces, obtaining lubricant-infused surfaces of Fe@E-Zn@PFOA@PFPE.Results and discussion: The influences of the textured roughness and chemical composition on the surface wettability were systematically investigated. The Fe@E-Zn@PFOA@PFPE performs omniphobicity with small sliding angles and superior corrosion resistance compared with the superhydrophobic surface, owing to their multiple barriers, including infused lubricant, hydrophobic monolayers, and compact Zn electroplating coating. Thus, the proposed lubricant-infused surface may provide insights into constructing protective coatings for the potential applications of engineering metal materials.

No breakthrough has been made in petroleum exploration of the Sinian Dengying Formation in the southeastern Sichuan Basin as the major factors controlling the hydrocarbon accumulation of the Dengying Formation have not been well established, including the development period and distribution of the platform margin, the effectiveness of the source-reservoir combination and the reliability of the Cambrian pre-salt structural trap. Based on the interpretation of seismic data and hydrocarbon-source correlation, the distribution of the platform margin of the Sinian Dengying Formation in the southeastern Sichuan Basin was mapped. Moreover, the gas source rocks of the Dengying Formation were clarified according to geochemical characteristics of fluid inclusions, and the pre-salt structures were further confirmed by seismic forward modeling and experiments of prestack depth migration. Results showed that the sedimentary facies of the 4th member of Dengying Formation in the southeastern Sichuan Basin was platform margin of gentle slope type. The platform margin reservoir of the Dengying Formation and the Lower Cambrian source rocks constitute a favorable source - reservoir combination. The carbon isotope characteristics of gas in fluid inclusions indicate that some of the oil/gas in the Dengying Formation were contributed by the Doushantuo Formation source rocks. As the difference in seismic velocities between carbonate rocks and gypsum/salt beds may cause a reduction in the amplitude of pre-salt structures, the low-amplitude structures identified on current seismic profiles are underestimated instead of overestimated. Accordingly, the Sinian structural traps are confirmed to develop in the deep pre-salt sequences in the low-steep anticline belt, southeastern Sichuan Basin. On the basis of the above new understanding, we propose two types of hydrocarbon migration modes for the Sinian Dengying Formation in southeastern Sichuan Basin, including lateral migration of hydrocarbons generated from the Cambrian Qiongzusi Formation and vertical migration of hydrocarbons derived from the Sinian Doushantuo Formation. Lithologic traps at the platform margin and pre-salt structural traps within the platform are favorable targets for natural gas exploration.

Breakthroughs of oil and gas exploration have recently been achieved via several wells in marl reservoirs of the first member of the middle Permian Maokou Formation in the southeastern Sichuan Basin. As a new type of unconventional gas reservoir, a lot of attention was attracted. In order to understand lithological characte-ristics and pore characteristics of marl reservoirs, lithological, pore types and pore structure characterization, works were carried out based on field and core samples. Results show that: (1) The TOC content of the marl reservoirs, which is mainly in outer gently sloping facies, is 0.76%-1.1%, with an increasing trend from northwest to southeast, similar to porosity changes. (2) Reservoir spaces of the marls mainly include organic pores, inorganic pores and microfractures. The organic pores can be classified into independent organic pores, organic pores with talc and intergranular organic pores of pyrite. The inorganic pores can be classified into intergranular pores, intercrystalline pores, and crystal dissolved pores. The microfractures can be classified into talc fractures, grain boundary fractures, and stress fractures. Organic pores are not dominant in the marl reservoirs, while microfractures are the most important reservoir space. (3) Combined characterization of cryogenic nitrogen adsorption, cryogenic CO2 adsorption, high-pressure Hg injection experiments and CT scan show that pores of the marls are mainly ink-bottle shaped with narrow neck and wide body. Micropores, mesopores and macropores are developed, with pore diameters of about 0.4-100 nm. The marls have obvious lithologic heterogeneity and poor connectivity. Fractures have an important influence on the connected pores. The marl in the first member of the Maokou Formation is a new type of unconventional reservoir, which has complex mineral composition and special pore characteristics. Targeted acid fracturing technology should be strengthen to promote the exploration and production of the marl reservoir.

In order to study the preservation effect of modified atmosphere packaging combined with high power pulse microwave on crab meat, the treatment of different gas types and their composition ratio (100% CO2, 80% CO2+20% N2, 50% CO2+50% N2, 20% CO2+80% N2) combined with high power pulse microwave (HPPM, action frequency 200 Hz, 6 min) were set in the experiment. The changes of total bacterial colonies, total volatile base nitrogen (TVB-N) and thiobarbituric acid reactive substance (TBARS) of crab meat were measured during storage at 25 ℃. The results showed that the total bacterial colonies, TVB-N and TBARS of crab meat packaged with different modified atmosphere were lower than those of the control group, and the inhibition effect of 100% CO2 treatment group was the best. The modified atmosphere packaging combined with HPPM significantly (P

AbstractAmalgamation of the Yangtze and Cathaysia blocks in the context of Gondwana assembly in the early Paleozoic has been addressed for decades, but the far-field effects on the Yangtze Block during the amalgamation remain unclear. In this study, we outline the sequence stratigraphic framework of the Ordovician succession in the central-upper Yangtze Block and analyze provenance records in sandstone compositions, distributions, and detritus zircon U-Pb dating. The Ordovician succession in the central-upper Yangtze Block is subdivided into six third-order sequences, which were deposited mainly in a carbonate platform with restricted sediments in Tremadocian to early Floian stages, mixed terrigenous-carbonate deposits in mid- to late Floian stages, and open circulation sediments in Dapingian to middle Katian stages. These sequences show the central-upper Yangtze Block experienced syn-tectonic deformation with northeast-trending long-wavelength uplift and depression alternatively and the depocenter shifting from the east during Tremadocian to mid-Floian stages to the southwest in late Floian to early Hirnantian stages. Provenance data indicate that detritus in the Ordovician succession was mainly from the northern India and Kangdian paleohighland to the southwest of South China Block. Incorporating the depositional and deformation variations, we propose a retroarc foreland basin that was developed on the South China Block in response to final suturing between the South China Block and East Gondwana at Sanya suture zone. The South China Block was thus involved in the global tectonics of the Gondwana supercontinental cycle during the Ordovician.

Superhydrophobic flexible strain sensors, which combine superhydrophobic coatings with highly sensitive flexible sensors, significantly enhance sensor performance and expand applications in human motion monitoring. Superhydrophobic coatings provide water repellency, surface self-cleaning, anti-corrosion, and anti-fouling properties for the sensors. Additionally, they enhance equipment durability. At present, many studies on superhydrophobic flexible sensors are still in the early research stage; the wear resistance and stability of sensors are far from reaching the level of industrial application. This paper discusses fundamental theories such as the wetting mechanism, tunneling effect, and percolation theory of superhydrophobic flexible sensors. Additionally, it reviews commonly used construction materials and principles of these sensors. This paper discusses the common preparation methods for superhydrophobic flexible sensors and summarizes the advantages and disadvantages of each method to identify the most suitable approach. Additionally, this paper summarizes the wide-ranging applications of the superhydrophobic flexible sensor in medical health, human motion monitoring, anti-electromagnetic interference, and de-icing/anti-icing, offering insights into these fields.

Marching deeper into the earth is of great significance for domestic resource strategy and tends to be an inevitable research direction in geoscience. With theoretical and technological progress achieved in recent years, hydrocarbon resources in deep or ultra-deep reservoirs have become a major exploration field for targets at home and abroad. Various discoveries of large-scale geological resources, such as H2, He, CO2 and geothermal resources, are proved to be related to deep geological processes, and therefore it is important to reveal the impact of these on deep accumulations. In this paper, the effects of basinal deep processes on hydrocarbon generation and evolution of source rocks, formation and preservation of reservoirs, migration and accumulation of hydrocarbon and its associated resources were discussed. Besides, some research progress and key scientific issues were summarized, and subsequently several research directions were proposed. Presently main scientific issues regarding deep geological processes and deep resources include: a) chemical kinetic models and multiple hydrocarbon generation potential of source rocks in deep geological processes; b) interaction mechanism of water-rock-hydrocarbon in high-pressure and high-temperature supercritical systems and effectiveness of ultra-deep reservoirs; c) phase transformation, accumulation and preservation of hydrocarbon in deep oil and gas systems; d) generation and accumulation of hydrocarbon-associated resources in specific deep geological environments. To carry out research on deep geological processes and deep hydrocarbon resources, it is necessary to start with the geological evolution of sedimentary basins, centering on the key issues of deep geological processes and resource effects and taking typical basins with active deep fluids as research objects, and revealing the mechanism of physical and chemical functions of deep formation, finally clarifying the impact of deep geological processes on the formation and accumulation mechanism of deep resources (oil and gas, H2, CO2, He, geothermal resources and hot dry rocks) and exploring the frontiers of deep resources. The main research directions in the future include: a) deep geodynamic settings and mechanism of geological processes; b) deep hydrocarbon generation kinetics and quantities; c) formation and preservation mechanisms of deep reservoirs; d) migration and accumulation mechanisms of deep hydrocarbons; e) differential enrichment mechanism of deep hydrocarbon-associated resources. Based on the above research, the accumulation theories and evaluation methods of hydrocarbon under the influence of deep geological processes were improved, and some scientific evidence for the exploration and evaluation of deep hydrocarbon-associated resources were provided.

By comparing the quantitative pore results of geological samples from natural evolution profiles and simulated experiment samples, it is believed that the volume changes of pores of different scales are basically similar throughout the evolution of source rocks. Macropores and mesopores have a greater impact on pore changes. They should be the main contributors to the total porosity of rocks, and there is a certain conversion relationship between pores of different sizes. Diagenetic evolution and tectonic changes are the main external factors that cause pore changes while hydrocarbon generation and expulsion processes are the internal factors. In addition, there are some differences in the pore space and size (scale) of hydrocarbon products formed by source rocks during different evolutionary stages. This is useful for determining the storage mechanism of conventional and unconventional oil and gas resources corresponding to different evolutionary stages in the shale formation.

A suite of Paleogene mafic rocks was collected from boreholes in the Huimin Sag of the Jiyang Depression with the aim of investigating the petrogenesis and nature of mantle source for these rocks and further providing insights into the characteristic of related mantle plume. Whole-rock geochemical data indicate that the mafic rocks have relatively lower SiO2 (42.93%–48.57%) contents and similar characteristics to alkaline basalt and belong to transitional calc-alkaline series. These samples were clearly enriched in LREEs and depleted in HREEs and were also characterized by the enrichment of LILEs, incompatible elements, and HFSEs, similar to those of the Ocean Island Basalt (OIB). In addition, they exhibited Pb enrichment; Y, Pr, and Yb depletion; absence of Nb-Ta anomalies; high Hf and low Zr; and Rb/Yb ratios exceeding 1.0, indicating characteristics of intraplate rift-type alkaline basalt. The samples exhibited (Th/Ta)PM and (La/Nb)PM ratios less than 1 and plotted within the OIB, EMI, and EMII fields, indicating that crustal components had no role in the generation of the rocks. With the exception of individual samples that have a distinctive range of εNd values, the majority of samples have complex εNd values of -1.15 to 5.56, indicating a mixture of different sources, which was also apparent in the δ18O-87Sr/86Sr diagram, in which the samples plot close to the downward nonlinear curve. Based on the isotopic and trace elemental analyses, these igneous rocks are intraplate rift-type alkaline basalt and are of mantle plume origin. The variations in 87Sr/86Sr, 143Nd/144Nd, εNd values, LREEs, and HFSEs were probably due to the different locations of the mantle plume for different samples. The primary magma of the rocks likely originated from the melting of a mantle plume and the further metasomatism of lithospheric mantle, continental, or oceanic crust.

In order to solve the problem that the air-to-ground data transfer rate is much lower than the radar data rate, the onboard system is commonly used for storing the airborne radar data. However, there are two main problems in the data storage using the traditional file management method. The first is that the frequent data updating of the file allocation table (FAT) and the file directory table (FDT) cause a high frequency of address jumps among the discontinuous areas, which leads to a long response time. The second is that the updating frequencies of the FAT, the FDT and the data region are seriously inconsistent, which results in uneven wear of the three areas. To solve these two problems, a file management method, which optimizes the data writing in the three areas of the FAT, the FDT and the data region, is proposed in this study. An actual measurement is carried out on a data storage system of the airborne radar using the proposed file management method. The result shows that the proposed method significantly reduces the updating frequency of FAT and FDT, and achieves the wear levelling of file area and data region.

With the hope to provide guidance to the design of additive manufactured porous orthopaedic implants and bone substitutes, three different topological porous structures (primitive, gyroid, bcc) with a porosity of 65% were designed and fabricated by selective laser melting using Ti-6Al-4V powders. The compressive and tensile properties of the porous scaffolds were investigated using quasi-static compression and tensile tests, respectively. Deformation behaviors of porous structures were analyzed by finite element simulation at different compression strains and loading condition. The Gyroid scaffolds have the highest compressive strength and tensile strength of 392.1 MPa and 321.3 MPa, respectively, almost two times higher than that of BCC scaffolds. Permeability of the scaffolds was measured using the falling head method and compared with the results of the computational fluid dynamics. The results showed that the permeability of the Gyroid scaffolds was about 20% that of the BCC scaffolds. It was suggested internal architecture for porous Ti alloy scaffold could significantly affect the mechanical stress and permeability.

Shale gas in Upper Ordovician Wufeng Formation–Lower Silurian Longmaxi Formation in the Sichuan Basin is one of the key strata being explored and developed in China, where shale gas reservoirs have been found in Fuling, Weiyuan, Changning and Zhaotong. Characteristics of shale gas enrichment in the formation shown by detailed profiling and analysis are summarized as “high, handsome and rich”. “High” mainly refers to the high quality of original materials for the formation of shale with excellent key parameters, including the good type and high abundance of organic matters, high content of brittle minerals and moderate thermal evolution. “Handsome” means late and weak deformation, favorable deformation mode and structure, and appropriate uplift and current burial depth. “Rich” includes high gas content, high formation pressure coefficient, good reservoir property, favorable reservoir scale transformation and high initial and final output, with relative ease of development and obvious economic benefit. For shale gas enrichment and high yield, it is important that the combination of shale was deposited and formed in excellent conditions (geological construction), and then underwent appropriate tectonic deformation, uplift, and erosion (geological transformation). Evaluation based on geological construction (evolution sequence from formation to the reservoir) includes sequence stratigraphy and sediment, hydrocarbon generation and formation of reservoir pores. Based on geological transformation (evolution sequence from the reservoir to preservation), the strata should be evaluated for structural deformation, the formation of reservoir fracture and preservation of shale gas. The evaluation of the “construction - transformation” sequence is to cover the whole process of shale gas formation and preservation. This way, both positive and negative effects of the formation-transformation sequence on shale gas are assessed. The evaluation models based on this strategy would be more accurate, reliable and would avoid bias derived from indiscriminate and simplistic use of all parameters in the models.

Taking the Well JY1 and Well PY1 in the Eastern Sichuan Basin as examples, the formation mechanism of shale gas overpressure was studied by using the cross plot of acoustic versus density logging data. During the processes of hydrocarbon generation and the uplifting, the pressure evolution of fluids in shale gas layers was reconstructed by fluid inclusions and PVTSIM software. The major factors controlling the evolution of shale gas overpressure were established according to the study of fracture, the timing of the uplifting, and episodes of tectonic deformation. Our results showed that the main mechanism of overpressure in the Silurian shale gas reservoirs in the Sichuan Basin was the fluid expansion, which was caused by hydrocarbon generation. Since the Yanshanian, the strata were uplifted and fluid pressure generally showed a decreasing trend. However, due to the low compression rebound ratio of shale gas reservoir rocks, poor connectivity of reservoir rocks, and low content of formation water and so on, such factors made fluid pressure decrease, but these would not be enough to make up the effects of strata erosion resulting in a further increase in fluid pressure in shale gas reservoirs during the whole uplifting processes. Since the Yanshanian, the Well PY1 zone had been reconstructed by at least three episodes of tectonic movement. The initial timing of the uplifting is 130 Ma. Compared to the former, the Well JY1 zone was firstly uplifted at 90 Ma, which was weakly reconstructed. As a result, low-angle fractures and few high resistance fractures developed in the Well JY1, while high-angle fractures and many high resistance fractures developed in the Well PY1. In totality, the factors controlling the overpressure preservation in shale gas reservoirs during the late periods include timing of late uplifting, superposition and reconstruction of stress fields, and development of high-angle fractures.

Natural serpentine powders are applicable as additives for various lubricating oils. However, no uniform theories explain their tribological performance, lubrication, and wear mechanism, especially their self-repairing mechanism. Herein, the influence of different nano serpentine powders (NSPs) contents in liquid paraffin on the friction and wear characteristics of steel balls and the self-repairing process of NSPs on the worn surface were studied. Results show that the optimal amount of NSPs was 0.5 wt %. Relative to those of the base oil, the friction coefficients and wear spot diameters were reduced by 22.8% and 34.2%, respectively. Moreover, the long-term tribological test shows that the wear scar diameter decreased slightly after 3 h, reaching the state of dynamic balance between wear and repair. The outstanding tribological performance should be attributed to the formed bilayer tribofilm, the first layer of which contains nanoparticles surrounded by lubricants and the second layer of which contains nanoparticles compacted onto the surface of the steel ball.

Typical unconventional gas/liquid plays of China were studied using field-emission/focused ion beam scanning electron microscopy (SEM) for clay mineralogy and microstructural development. The SEM microstructural investigations of clay-rich shale and mudstone reservoirs provided significant information about clay mineral type, size, distribution and aggregates, which allows for interpretations regarding porosity preservation and petrophysical variability. The major clay-hosted porosity types are interparticle clay pores, intraparticle clay pores and aggregate pores. Interparticle clay pores occur in open spaces of the clay aggregates and include four subtypes: (1) elongated pores, (2) packed pores, (3) jagged pores and (4) card-house pores. Intraparticle clay pores are present within clay particles and have mostly secondary origin. These pores are diagenesis dependent and are restricted to secondary illite particles during the transformation of clay minerals from smectite to illite. Intraparticle clay pores constitute only isolated porosity and could not contribute to hydrocarbon molecule storage and migration. Aggregate pores were predominantly encountered in association with organic–clay and pyrite– clay aggregates. In places, organic–pyrite–clay aggregates can also display polymerization, but they do not contribute significantly to overall porosity and permeability. Combining SEM morphological analyses with the software ImageJ is critical in clay microstructure and porosity analyses via semi-quantitative characterization of the 3D pore surface, 2D pore profile, pore quantity, pore size, areal por)osity, etc. These visual and semi-quantitative results highlight the significance of jagged pores and pyrite–clay aggregate pores in shale gas/liquid reservoirs because they may be important facilitators of gas storage and transmission. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the role and mechanisms of action of long non-coding RNA (lncRNA) (LINC00461) in breast cancer. Methods: Human breast cancer cell lines and normal mammary epithelial cell lines as well as their corresponding negative controls (NC) were cultured and co-transfected with Lipofectamine 3000. Expressions of LINC00461 and miR-607 were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR), while the SLC1A3 level was evaluated by western blot. The role of LINC00461 in cell proliferation, apoptosis, cycle arrest, glycolysis, and chemoresistance was determined by MTT, colony formation, flow cytometry, and ELISA assays. Results: The LINC00461 level was overexpressed in breast cancer cell lines (p ˂ 0.05). Knockdown of LINC00461 in MCF-7 cells inhibited cell viability (p ˂ 0.01) and the degree of colony formation (p ˂ 0.001), induced cell apoptosis (p ˂ 0.001) and cycle arrest (p ˂ 0.01), and suppressed glucose consumption (p ˂ 0.001), lactate production (p ˂ 0.001), LDHA activity (p ˂ 0.05) and cisplatin sensitivity (p ˂ 0.05). Overexpression of LINC00461 in MDA-MB-468 cells resulted in reverse outcomes. LINC00461 positively regulated the expression of SLC1A3 via miR-607 in breast cancer cells. It was mechanistically established that LINC00461 is bound to miR-607 and miR-607 bound to SLC1A3, and this was confirmed by luciferase assay. Conclusion: LINC00461 induces cell proliferation, cycle arrest, glycolysis, and chemoresistance by modulating miR-607/SLC1A3 axis in breast cancer. The results lay the theoretical basis for monitoring and therapy of breast cancer. [ABSTRACT FROM AUTHOR]