Pore characteristics are one of the most important elements in the study of shale reservoir properties and are a key parameter for the evaluation of the potential of shale oil and gas resources. Low-temperature nitrogen adsorption is a common laboratory method that is used to characterize the pore structure of shale. However, the effect of shale’s particle size on the experimental results of the nitrogen adsorption of deep shale samples is still unclear. In this paper, using deep shale samples of different mesh sizes from the Luzhou Block as an example, we studied the effect of particle size on the pore structure of deep shale, as characterized by nitrogen adsorption experiments. The results showed that the pore volume of deep shale is mainly distributed in the mesoporous range, with a pore size ranging from 2 to 20 nm. The pore volume, as measured by nitrogen adsorption, increases slowly as the particle size decreases and then it increases rapidly. The particle size of shale has no obvious effect on the measurement of the specific surface area. The fractal dimension of deep shale gradually increases as the particle size of the shale samples increases and the smaller the particle size, the higher the correlation coefficient, R², of the fractal dimension fitting. In this paper, different recommended sizes are given for selecting suitable particle sizes in nitrogen adsorption experiments on deep shale with different structural parameters, which will increase the accuracy of the study of the pore structure of deep shale.

Carbon fiber reinforced polymer (CFRP) tendons are composite materials that offer significant advantages in terms of tensile strength and lightweight properties. They are being increasingly utilized in the construction industry, particularly in bridge cables and building structures. However, due to their relatively poor transverse mechanical properties compared to steel cables, securing these tendons with anchors presents a challenge. This paper reviews the structure and force characteristics of three types of anchors for CFRP tendons—clamping anchorage, bonded anchorage, and composite anchorage—analyzes and summarizes the anchorage characteristics and damage mechanisms of each type of anchorage, and highlights that the optimization of the mechanical properties of the tendons is key to the design and research of anchoring systems. The new composite anchorage offers comprehensive advantages, such as minimal tendon damage at the anchorage section, more uniform stress distribution, and better anchorage performance, despite being more complex in design compared to single-type anchorages. However, there remain challenges and research gaps in testing and validating these anchoring systems under realistic loading and environmental conditions, including impacts, cyclic stresses, humidity, and high temperatures. Future efforts should focus on developing new testing techniques and models to simulate real-world conditions, enabling more accurate assessments of anchorage performance and longevity. By doing so, we can fully harness the mechanical properties of CFRP tendons and further enhance the safety and efficiency of our built environment.

Emulsification plays a pivotal role in the process of enhanced oil recovery, especially in chemical flooding. Surfactant–polymer flooding is a promising technique with significant potential for improving oil recovery in medium and high permeability oilfields in China. Emulsification has emerged as one of the key mechanisms facilitating oil recovery in surfactant–polymer flooding. This study aimed to assess the effects of surfactant structure and concentration, polymer, oil–water ratio, clay content, and injection rate on the formation of different emulsion types and their stabilities. The assessment was conducted based on the actual conditions of surfactant–polymer flooding in the Qizhong area of the Xinjiang oilfield. The findings revealed that KPS-1 (petroleum sulfonate) demonstrated superior emulsifying and solubilizing abilities for crude oil compared to BS-18 (betaine), whereas BS-18 exhibited better emulsifying stability. KPS, which was a combination system of KPS-1 and BS-18, displayed favorable emulsifying ability. However, the emulsifying stability of the three surfactants decreased in the presence of HPAM (hydrolyzed polyacrylamide). The oil–water ratio primarily influenced the morphology of the emulsion. When the oil–water ratio exceeded 6:4, a water-in-oil emulsion was formed, and the viscosity of the emulsion reached its maximum at an oil–water ratio of 7:3. Moreover, clay demonstrated a significantly high ability to emulsify, resulting in the formation of emulsions with increased viscosity and robust stability. Regarding the injection rate, effective emulsification occurred when the injection rate reached 1 m/d, while emulsions with high viscosity were observed at an injection rate of 7 m/d.