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Pore‐throat structure is a key factor that influences the storage and fluid flow capacity of tight sandstone reservoirs. Taking the tight sandstone reservoir of Xu2 Fm in Zhongba area as an example, the reservoir quality, pore‐throat type and pore size distribution of tight sandstone in the study area were described by casting thin section, scanning electron microscope and high‐pressure mercury injection test. In order to quantitatively characterize the complexity and heterogeneity of pore‐throat structure, fractal analysis was performed using mercury saturation and pore size data. This study mainly reveals the relationship between the geometric shape characteristics and fractal dimension of the binary pore structure of ultra‐low permeability tight sandstone and clarifies the influence of different scale pore throats on reservoir physical properties. The results indicate that the physical properties of the reservoir in the study area are poor, the pores are mainly intergranular pores and dissolution pores, the throat is flake and necked and the pore size distribution range is large. The fractal curve obtained by the mercury saturation method shows a significant turning point, and the pore‐throat system is divided into two types: small‐scale and large‐scale. The fractal dimension of large‐scale pore throat is greater than the three‐dimensional Euclidean space dimension, which does not conform to the fractal theory. The fractal dimension of small‐scale pore throat is closely related to the pore‐throat structure and has obvious fractal characteristics. The geometric shape of binary pore‐throat structure in tight sandstone is the main factor affecting the difference of fractal dimension. The development of small pores in sandstone is positively correlated with the total porosity, but its contribution to permeability is relatively low. The physical properties of tight sandstone are mainly controlled by the development degree of large‐scale pore throat. [ABSTRACT FROM AUTHOR]

In the early twentieth century, traditional handicraft was challenged by the latest technology in China. It is reflected by ethnic costumes combining new and old, as in the waistcoat of this study. This waistcoat made at Gyalrong Tibetan area in Sichuan, China, displays unique local features in terms of its brilliant colors and comprehensive craftsmanship. This study employs techniques such as optical microscopy, infrared spectroscopy, scanning electron microscope and high performance liquid chromatography-mass spectrometry to investigate various aspects of this waistcoat, including its fabrics and dyes. The results showed that the waistcoat was primarily made of cotton and silk, with a bamboo paper layer, and that silk as well as twisted gold and silver threads were employed for the embroidery. Various embroidery techniques were applied, with patterns, color combinations, and characteristics being consistent with those of Tibetan and Shu (蜀) embroidery. In terms of dyeing technology, a wide range of colors were achieved through multi-step dyeing processes using natural dye stuffs like pagoda bud, and synthetic dyes like magenta. These findings indicates that modern technologies were well integrated into traditional garment manufacture in the early twentieth century in China. [ABSTRACT FROM AUTHOR]

Diagenesis is a series of physical and chemical reactions that take place after deposition. Using cores, thin sections, cathode luminescence, X-ray diffraction, scanning electron microscope, inclusions analysis, geochemical analysis and pore permeability data, the diagenesis, and its influence on the tight sandstone reservoir of Xu 2 member in the southwest Sichuan Basin has been analyzed. The reservoirs of the southwest Sichuan Basin mainly consist of feldspathic feldspathic sandstone, feldspathic feldspathic sandstone, and felsic sandstone, with an average porosity of 3.57% and an average permeability of 0.138·10-3 μm2, which are typical tight sandstone reservoirs. The sandstones in the Xu2 member mainly underwent compaction, dissolution, cementation and accounting, and the specific evolution process is compaction , first-phase fracture, first-phase quartz increase, first-phase calcite cementation, second-phase fracture, feldspar and rock chip dissolution, second-phase quartz increase and silica filling, chlorite cementation or illite cementation, second-phase calcite cementation, dissolution, third-phase quartz increase and silica filling, the third stage of carbonate cementation, carbonate accounting for feldspar and quartz- third stage of tectonic fragmentation, late calcite or quartz cementation into rocks. And the rock formation stage is mainly mesodiagenesis B stage. The secondary pores and microfractures are the main reservoir space in the Xu 2 member sandstone reservoirs. Strong compaction and carbonate cementation are the main reasons for the tight sandstone reservoir, and dissolution and fracture are the main constructional effects for the development of the dominant reservoir. [ABSTRACT FROM AUTHOR]