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The Fuxing area of the Sichuan Basin is known for its multiple sets of organic-rich shale in the Jurassic period, with several wells yielding significant amounts of industrial oil and gas. Understanding the characteristics and factors influencing the enrichment of different shale facies sedimentary reservoirs is crucial for effective exploration. Through detailed rock core descriptions, experimental analysis, and drilling exploration, the author has classified and compared fine-grained sedimentary rock facies in terrestrial strata, characterized reservoirs, identified types of oil and gas reservoirs, and analyzed the main factors influencing enrichment and productivity. The study reveals that the Jurassic strata in the Fuxing area contain two sets of high-quality shale with semi-deep lacustrine facies: the first sub-section of the Dongyuemiao section of the Ziliujing Formation and the lower sub-section of the second section of the Lianggaoshan Formation. These shale layers exhibit multi-layer stacking, moderate TOC content, well-developed bedding, integrated source storage, and high gas/oil ratio characteristics. The lithology of these target shale layers is complex, leading to the establishment of a four-element lithofacies classification scheme based on "color-TOC-sedimentary structure-mineral composition". This scheme identifies the gray-black high carbon sand-laminated clay shale as the favorable lithofacies for the lower sub-section of the second section of the Lianggaoshan Formation, and the gray-black high carbon medium debris-laminated and fine sand medium debris-laminated clay shale as the favorable lithofacies for the eastern sub-section. The three lithofacies in the study area are horizontally distributed in a stable manner. The gray-black high carbon fine sand layer, medium debris layer, and fine sand-medium debris layer type clay shale exhibit reservoir characteristics of "porous coexistence, large pores and throats, and integrated pores and fractures". These reservoir properties, including good permeability, facilitate the efficient storage and flow of shale oil and gas in the pore-fracture storage system. The first sub-section of the Dongyuemiao section is a condensate gas reservoir, while the lower sub-section of the Lianggaoshan Formation's second section is a volatile oil reservoir. Key factors contributing to the enrichment of continental shale oil and gas have been identified, including medium to high hydrocarbon generation potential and strong retention rates supporting the accumulation of laminated shale oil and gas. A favorable hydrocarbon-diagenesis-reservoir formation configuration promotes oil and gas accumulation. Additionally, the development of micro cracks and suitable thermal evolution aids in hydrocarbon enrichment and flow, while large, wide, gentle synclines and high-pressure overpressure conditions support the sustained preservation of hydrocarbons.

Abstract RNA interference (RNAi) is a powerful tool for understanding and manipulating signaling pathways in plant science, potentially facilitating the accelerated development of novel plant traits and crop yield improvement. The common strategy for delivering siRNA into intact plants using agrobacterium or viruses is complicated and time‐consuming, limiting the application of RNAi in plant research. Here, a novel delivery method based on mesoporous silica nanoparticles (MSNs) is reported, which allows for the efficient delivery of siRNA into mature plant leaves via topical application without the aid of mechanical forces, achieving transient gene knockdown with up to 98% silencing efficiency at the molecular level. In addition, this method is nontoxic to plant leaves, enabling the repeated delivery of siRNA for long‐term silencing. White spots and yellowing phenotypes are observed after spraying the MSN‐siRNA complex targeted at phytoene desaturase and magnesium chelatase genes. After high light treatment, photobleaching phenotypes are also observed by spraying MSNs‐siRNA targeted at genes into the Photosystem II repair cycle. Furthermore, the study demonstrated that MSNs can simultaneously silence multiple genes. The results suggest that MSN‐mediated siRNA delivery is an effective tool for long‐term multi‐gene silencing, with great potential for application in plant functional genomic analyses and crop improvement.

The southeastern Sichuan Basin is one of the key targets for shale gas exploration in China. Currently, the exploration has gradually been delved into deep and ultra-deep formation fields. However, due to various constraint factors such as drilling and earthquakes, research on the tectonic characteristics and shale gas preservation conditions in this area is inadequate. In order to find out the tectonic deformation characteristics of Qijiang high-steep complex tectonic belt in southeast Sichuan and its impact on the enrichment law of deep shale gas, and to provide a basis for subsequent exploration deployment, a high-steep structural model is established based on the analysis of tectonic deformation characteristics and practice drilling data, and the quantitative evaluation of the main controlling factors of differences in preservation conditions is carried out on the basis of the model. The research results show that: (1) Qijiang high-steep structure has the layered deformation feature of "steep upper part and flat lower part + dominated by gypsolyte + steep front"; (2)There is a widely developed Cambrian gypsum salt layer in the Qijiang area, whose plastic deformation controls the uplift of the overlying structure; (3) The factors affecting the preservation conditions of shale gas in the study area include active deformation strength, fracture system, normal stress of fault plane, angle between structure and geostress, roof detachment layer and other factors. The interaction of multiple factors leads to obvious differences in the preservation conditions in the study area. According to the analysis results, the evaluation criteria for the preservation conditions of Qijiang high-steep structures are established, and it is defined that the Longsheng-Taozidang tectonic belt has single tectonic stress, low active deformation intensity and well-closed structure, which is the main favorable target for the next exploration.

In order to clarify the genesis of "low resistivity and low gas content" in the shale of Wufeng-Longmaxi formations and effectively guide the next step of shale gas exploration in Sichuan Basin, a detailed study on the problem based on a large number of drilling surveys, dissections, and analysis of laboratory test results in the entire area was carried out herein. Low-resistivity wells of Longmaxi Formation shale in this area can be divided into two types based on their electrical and geological characteristics, which are less than 1 Ω·m and 1-10 Ω·m. Shale gas wells with resistivity less than 1 Ω·m are basically gas-free and mostly dry wells with relatively concentrated distribution areas, mainly located in southwestern Sichuan and western Changning. The resistivity curve of the shale exhibits a "thin neck" characteristic, with a Raman reflectance generally above 3.70% and a high amplitude graphite peak. In addition, the variation range of resistance values in rock electrical experiments under different states is small, and they all exhibit extremely low to low resistance characteristics, indicating that the conductivity of the rock skeleton caused by graphitization is the main factor affecting this type of shale. The drilling distribution area of shale with resistivity in the range of 1-10 Ω·m is relatively wider, mainly with slight gas content, distributed both inside and outside the basin. The characteristics exhibited by its electrical properties, laser Raman, and rock electrical experiments are significantly different from those of shale less than 1 Ω·m. The resistance curve of this type of shale exhibits a "gradual" characteristic, with a measured Raman reflectance of around 3.50% by laser Raman spectroscopy. The laser Raman spectrum also does not show obvious graphite peak characteristics. This type of shale undergoes a wide range of changes in rock electrical experiments under two states: dry water and saturated water, with a change in shale resistivity of 7 to 20 times before and after drying, and exhibits medium to high electrical resistance characteristics, revealing a significant impact of shale water content on shale resistivity. Based on actual drilling data, it is believed that the deterioration of shale gas preservation conditions and the increase in water content are the main reasons for this type of low-resistivity well.

Fruitful achievements have been made in shale gas exploration in the middle and deep areas from the Upper Ordovician Wufeng Formation to the Lower Silurian Longmaxi Formation in the southeastern Sichuan Basin, and in the research on shale reservoir characteristics and main controlling factors. As the key direction of current shale exploration, the deep and ultra-deep areas are limited by drilling and other factors, and the research on reservoir development characteristics and differences with the middle and deep shale reservoirs is insufficient. In order to clarify the characteristics of the deep and ultra-deep shale reservoirs of the Wufeng-Longmaxi formatiosns, four typical shale gas wells at the depth of 2 000-6 000 m in the southeastern Sichuan exploration area were selected to systematically carry out a comparative study of deep and ultra-deep shale reservoir development characteristics and differences, and the causes of pore development were discussed. The results show that: (1) With a burial depth of less than 6 000 m, the shale reservoirs of the Wufeng-Longmaxi formations are effective reservoirs with high porosity, and the porosity has no obvious change with the change of burial depth. However, there are certain differences in the morphology, structure and connectivity of organic matter pores, that is, with the increase of burial depth, the size of organic matter pores relatively decreases, and the pore connectivity deteriorates; (2) It has been clarified that biogenic silica is the foundation of pore development, and fluid overpressure is the key to maintaining reservoir pores. Under the combined action of biogenic silica and biogenic silica, the deep and ultra-deep shale reservoirs with high porosity and high quality can be developed and maintained; (3) Based on the research of reservoir development, shale gas exploration will be extended to 6 000 m, which provides a clear direction for shale gas exploration in the next step. It is preliminarily assessed that the deep and ultra-deep shale gas (buried depth of 4 000-5 000 m) resources in the Wufeng-Longmaxi formations in the Sichuan Basin and its surrounding areas exceed 2×1012 m3.

Well Taiye 1 in the Fuling area of the eastern Sichuan Basin has obtained a high-yield industrial gas flow (7.5 × 104 m3/d gas and 9.8 m3/d oil) from the Middle Jurassic Lianggaoshan Formation, presenting a good test production effects, which means the realization of a major breakthrough in the exploration of Jurassic lacustrine shale oil and gas in the Sichuan Basin. In order to further determine the exploration potential of lacustrine shale oil and gas in this area and realize the large-scale efficient development and utilization of lacustrine shale oil and gas, this paper analyzes the geological conditions for the accumulation of lacustrine shale oil and gas in this area by using the drilling data of 10 key wells, such as wells Taiye 1 and Fuye 10. Then, the main factors controlling the enrichment of lacustrine shale oil and gas are discussed, and the exploration potential and favorable target zones of Jurassic lacustrine shale oil and gas in the Fuling area are defined. And the following research results are obtained. First, the quality Jurassic semi-deep lake shale in the Fuling area is characterized by high organic matter abundance, high porosity and high gas content, and it is the geological base of shale oil and gas enrichment. Second, the developed large wide and gentle syncline, good preservation condition and higher pressure coefficient (generally >1.2) are the key to the enrichment and high yield of shale oil and gas. Third, the developed microfractures in lacustrine shale are conducive to the enrichment and later fracturing of shale oil and gas. In conclusion, the Lianggaoshan Formation lacustrine shale in the Fuling area is widely distributed with moderate burial depth, developed microfractures and moderate thermal evolution, and its shale gas resource extent and shale oil resource extent are 1 922 × 108 m3 and 2800 × 104 t, respectively, indicating greater potential of shale oil and gas exploration, so shale oil and gas is the important field of oil and gas reserves and production increase in this area in the following stage.

Carbonate rocks in the first member of the Middle Permian Maokou Formation in the Sichuan Basin (hereinafter “Mao 1 Member” for short) have been taken as a set of carbonate source rocks, and they have not been specifically studied from the aspects of reservoir evaluation and testing. By referring the exploration ideas of unconventional natural gas, the Mao 1 Member in Fuling area of southeastern Sichuan Basin has obtained industrial gas flow in development wells in recent years. In order to further clarify the natural gas exploration potential of the Mao 1 Member in this area, it is necessary to study its sedimentary characteristics, natural gas accumulation conditions and main control factors based on the data of field section measurement, systematic coring in drilling and laboratory testing. The following research results were obtained. First, the gas reservoir in the Mao 1 Member in the Fuling area is of source–reservoir integration, and its natural gas is mainly enriched in blackish gray marlite and nodular marlite. Second, its reservoir spaces are dominated by grain margin pores (fractures), diagenetic shrinkage pores (fractures), organic pores and fractures. Third, the pores are mostly in nanometer scale, and the main pore diameter is in the range of 5–50 nm, which is between shale reservoir and conventional reservoir, with strong heterogeneity. Fourth, the gas reservoir is characterized by source–reservoir coexistence, lithology controlling reservoir and extensive layered distribution, presenting two-stage differential hydrocarbon enrichment, namely intraformational near-source enrichment in the early stage and interformational blowdown adjustment in the late stage. Fifth, the development of blackish gray organic-rich fine marlite which is deposited with the episodic upwelling in the outer ramp facies belt is the foundation for the natural gas accumulation, the transformation of clay minerals controls the development of higher-quality reservoirs, good preservation conditions are the key to the natural gas accumulation, and fracture development is favorable for the enrichment and high yield of natural gas. In conclusion, the Mao 1 Member in this area is a special type of gas reservoir, i.e., carbonate source rock gas reservoir, which has greater potential of natural gas exploration and industrial gas flow have been obtained in several wells. The discovery of such type of gas reservoirs not only expands the domain of natural gas exploration in the Sichuan Basin, but provides the reference for the natural gas exploration in other areas of South China.

The fracturing of the Paleozoic marine shale in the Sichuan Basin and its periphery was studied. The disruptive effects of faulting on shale gas preservation were analyzed based on the comprehensive interpretation of seismic structure, the analysis of fluid inclusions in calcite veins in fractures in shale layers, and the consideration of typical shale gas wells with different gas-bearing properties. Fault level, spatial stacking pattern, stage and duration have an important influence on the preservation conditions of shale gas. (1) The higher the fault level is, the larger the impact. The preservation conditions for shale gas are destroyed in the areas close to the first-level faults (within about 10 km), the second-level faults (within about 5 km), and the third-level faults (within about 2-3 km), but not influenced in the area close to the fourth-level faults. (2) Under the premise of similar fracture density in the well area, when different levels of faults intersect from parallel or small angles to large angles, the damage to shale gas preservation gradually increases. (3) The more fault activity periods and the longer their duration, the greater is the damage to shale gas preservation in the later period. Fault period and activity duration can be divided into 4 types: (1) short-term activity in the late Yanshan period, whose impact on preservation conditions was small; (2) intermittent activity in the Yanshan and early Himalayan periods where preservation conditions were affected to some extent; (3) continuous activity since the late Yanshan period, which caused serious damage to preservation conditions; and (4) continuous activity since the Himalayan period, which had a greater impact on preservation conditions.

With the continuing shale gas exploration and development in China, it is necessary to establish a scientific method to evaluate shale gas resources. This paper focuses on considering the heterogeneity of shale gas resource distribution and the impact of preservation conditions. On the basis of identifying the main influencing factors of shale gas "pressure coefficient", the study area is divided into A-type area (pressure coefficient >1.2), B-type area (pressure coefficient 1.0-1.2) and C-type area (pressure coefficient 0.8-1.0). By dissecting the shale gas calibrated area of Upper Ordovician Wufeng-Lower Silurian Longmaxi formations in Fuling, the resource volume is obtained as a key parameter for analog calculation, and the shale gas resources are evaluated by analogy. Comprehensive calculation of the total shale gas resources in the southeastern Sichuan area is 5.52×1012 m3, 4.04×1012 m3 of which is accounted for between 4 500-6 000 m depth, indicating that shale gas with a burial depth greater than 4 500 m in this area has a greater shale gas exploration potential.

Abstract Background Drought is one of the most serious factors limiting plant growth and production. Sheepgrass can adapt well to various adverse conditions, including drought. However, during germination, sheepgrass young seedlings are sensitive to these adverse conditions. Therefore, the adaptability of seedlings is very important for plant survival, especially in plants that inhabit grasslands or the construction of artificial grassland. Results In this study, we found a sheepgrass MYB-related transcription factor, LcMYB2 that is up-regulated by drought stress and returns to a basal level after rewatering. The expression of LcMYB2 was mainly induced by osmotic stress and was localized to the nucleus. Furthermore, we demonstrate that LcMYB2 promoted seed germination and root growth under drought and ABA treatments. Additionally, we confirmed that LcMYB2 can regulate LcDREB2 expression in sheepgrass by binding to its promoter, and it activates the expression of the osmotic stress marker genes AtDREB2A, AtLEA14 and AtP5CS1 by directly binding to their promoters in transgenic Arabidopsis. Conclusions Based on these results, we propose that LcMYB2 improves plant drought stress tolerance by increasing the accumulation of osmoprotectants and promoting root growth. Therefore, LcMYB2 plays pivotal roles in plant responses to drought stress and is an important candidate for genetic manipulation to create drought-resistant crops, especially during seed germination.

In addition to marine and marine-continental transitional strata, the continental ones are also widely distributed in various oil and gas-bearing basins in China. The continental shale generally provides favorable material bases for hydrocarbon generation, such as wide distribution, large thickness, multiple series of strata, high TOC content, nice organic matter type, and moderate thermal evolution. Part of such shale contains shale oil, but the pore space characteristics for the occurrence of this oil are not thoroughly studied. In order to accurately and quantitatively characterize the pore space where the continental shale oil in different types of lithofacies occurs, we sampled the rock cores from the Middle Jurassic Lianggaoshan Formation in the southeastern Sichuan Basin of the Upper Yangtze Area. The TOC content and mineral composition were analyzed, and we also carried out experiments on CO2 and N2 adsorptions, high-pressure mercury injection, and wash oil. Results show significant differences in pore space characteristics for the occurrence of shale oil in different types of lithofacies. In organic-rich mixed and clayey mudstones with the highest TOC content, the free shale oil, occupying the largest reservoir space, mainly occurs in macropores and mesopores, and the adsorbed shale oil, occupying the largest reservoir space, mainly occurs in mesopores. In the organic-bearing clayey mudstone, which has a higher TOC content, the free shale oil takes a larger reservoir space and mainly occurs in macropores, followed by mesopores, and the absorbed one, occupying a larger reservoir space, mostly occurs in micropores and then the mesopores. The organic-bearing mixed mudstone has a moderate TOC content, in which the free shale oil occupies a smaller reservoir space and primarily occurs in mesopores, followed by macropores, and the absorbed one, which takes a larger reservoir space, all occurs in mesopores. In the fine sandstone, the free shale oil occupies a smaller reservoir space and primarily occurs in mesopores, while the absorbed one occupies a smaller reservoir space and all occurs in mesopores.

Based on the understandings on enrichment rules of marine shale gas in southern China and data obtained from exploration and development in Fuling shale gas field, this article discusses the key controlling factors on shale gas enrichment and their relationships, it also discusses further the theory of Two-Factor Enrichment of marine shale gas in southern China. The bases for shale gas enrichment are shale gas generation and accumulation, the shale gas reservoirs of deep-water shelf are characterized by high TOC, high porosity, high gas contents and high siliceous contents, with high hydrocarbon-generation intensity. The organic pores are rich in shales in favorable for stimulation, so they are the bases for large scale hydrocarbon accumulation. Preservation conditions are vital to the formation and enrichment of shale gas reservoirs, good top and base layers can effectively prevent hydrocarbon from escaping vertically at the beginning of hydrocarbon generation. Shale gas preservation conditions depend on the intensity and duration of tectonic movements, good preservation conditions are key geological factors for shale gas accumulation, shale reservoirs have high gas contents, high porosity and high pressure and are likely to form high yield area of shale gas. Key words: Sichuan Basin, Fuling shale gas field, Lower Silurian, Longmaxi Formation, shale gas, enrichment and high production, controlling factors

Compelling evidence indicates that epigenetic regulations orchestrate dynamic macrophage polarization. N6-methyladenosine (m6A) methylation is the most abundant epigenetic modification of mammalian mRNA, but its role in macrophage polarization is still completely unknown. Here, we show that the m6Acatalytic enzyme methyltransferase like 3 (METTL3) is specifically upregulated following the M1 polarization of mouse macrophages. Furthermore, METTL3 knockdown through siRNA transfection markedly inhibited M1, but enhanced M2, macrophage polarization. Conversely, its overexpression via plasmid transfection greatly facilitated M1, but attenuated M2, macrophage polarization. Further methylated RNA immunoprecipitation and in vitro m6A methylation assays suggested that METTL3 directly methylates mRNA encoding signal transducer and activator of transcription 1 (STAT1), a master transcription factor controlling M1 macrophage polarization, at its coding sequence and 3=-untranslated regions. In addition, METTL3- mediated STAT1 mRNA methylation significantly increased mRNA stability and subsequently upregulated STAT1 expression. In conclusion, METTL3 drives M1 macrophage polarization by directly methylating STAT1 mRNA, potentially serving as an anti-inflammatory target. [ABSTRACT FROM AUTHOR]