Offshore infrastructure stability is controlled by deep-water shallow sediments, and the geotechnical-acoustic correlation between the two enables geological property prediction from acoustic waves. However, existing models often rely on limited sediment types or regional data, constraining their generalizability across a range of marine environments. This study presents a novel predictive model that uses a theoretical framework extending Biot's theory to integrate key geotechnical properties-clay content, density, water content, and shear strength-with acoustic parameters. By establishing the theoretical relationship between sediment parameters and acoustic responses, P-wave velocity and attenuation coefficients are computed under a range of conditions. Single-factor predictive models for each geotechnical property are derived through numerical fitting and rigorously validated against experimental data. These individual models are subsequently integrated into a comprehensive multi-factor model using multiple linear regression. Analysis of variance and Spearman’s correlation analysis statistically confirm that these four parameters exert a significant and substantial influence on acoustic wave behavior. The capability of the model to simultaneously invert for multiple geotechnical properties from acoustic datasets makes it a practical tool for pre-drilling sediment characterization, enabling a more reliable, non-invasive method for site investigation that can reduce planning risks and costs. By improving the accuracy of sediment property assessment, the model contributes directly to enhanced geohazard identification and mitigation strategies, thereby promoting greater safety in the development of deep-water marine resources.

The oxygen initiation process, one of the key processes in the early stage of the autothermic pyrolysis in-situ conversion technology, has not been deeply investigated, which seriously limits its development. In this study, the reaction behaviors, kinetic parameters, heat and product release characteristics during the isothermal oxygen initiation process of Huadian oil shale in O₂/N₂ mixtures with different oxygen concentrations and initiation temperatures were investigated via TG/DSC-FTIR. The results show that the samples exhibit three different reaction behaviors during the initiation stage, consisting of two main parts, i.e., the oxidative weight-gain and the oxidative reaction phases. The former phase is mainly characterized by the oxygen addition reaction that produces oxidizing groups which increase the sample mass. And the latter stage consists of two main subreactions. The first subreaction involves the oxidative cracking and pyrolysis of oxidizing groups and kerogen to produce fuel deposits such as residual carbon, while the second subreaction focuses on the oxidation of the resulting fuels. Furthermore, increasing the oxygen concentration significantly promotes the above reactions, leading to an increase in the reaction intensity and reaction rate. Owing to the combined effect of oxygen concentration and residual organic matter content, the total heat release increases with the increasing initiation temperature and reaches its maximum at 330–370 ℃. In addition, the preheating stage primarily produces hydrocarbon gases, while the initiation stage predominantly generates CO₂. As the preheating temperature increases, the CO₂ output intensifies, the required reaction time shortens, and the release becomes more concentrated. Based on these findings, a reaction mechanism for the oxygen initiation process of Huadian oil shale was proposed, and recommendations were provided for optimizing the construction process.

Given the abundance of clay minerals in oil shales, the in-situ cracking of oil shale is preferably enhanced by catalysis, such as by modifying reservoir clays with soluble catalytically active materials. In this work, nickel-modified montmorillonite was synthesized via a simple method, and the feasibility of in-situ catalytic cracking of oil shales to facilitate engineering implementation was investigated. Thermogravimetric analysis was performed to assess the impact of the catalyst on the pyrolysis behavior of kerogen. The results demonstrated that nickel-modified montmorillonite effectively reduces the initial cracking temperature of kerogen and enhances the hydrocarbon generation rate. The results of thermogravimetric-Fourier transform infrared spectrum and thermogravimetric-mass spectrometry analysis revealed a significant boost in the production of smaller molecules and non-condensable gases, including hydrogen, methane, ethane, and benzene. Concurrently, there was a notable reduction in carbon dioxide and sulfur dioxide emissions. Pyrolysis experiments were conducted to provide additional evidence of the effectiveness of nickel-modified montmorillonite, confirmed by a decrease in semi-coke production and a notable 11.25% increase in oil yield. Furthermore, the composition analysis of shale oil indicated an increased production of alkenes and aromatic hydrocarbons. These findings suggest that the addition of nickel-modified montmorillonite effectively enhances the depolymerization, deoxygenation and aromatization reaction, resulting in the formation of valuable products during the pyrolysis of oil shale kerogen. This study offers a promising avenue of cost-effective and efficient in-situ oil shale exploitation.

In the face of the complex global energy transition, the development of unconventional oil and gas resources, such as oil shale, shale oil, and shale gas, encounters challenges related to carbon neutrality, technological complexities, and costs. However, the world's strained energy landscape and the fact that the new energy industry has yet to take shape also present rich opportunities for the development of these resources. Against this background, a conference platform was established at Jilin University for facilitating scholarly exchange and discussion on the exploration and development technologies of shale oil and gas. The 5^th International Symposium on Shale Oil and Gas Exploration and Development Technologies was successfully held in Changchun from November 10 to 12, 2023. The symposium attracted over 210 experts and scholars from more than 59 institutions worldwide, representing the field of shale oil and gas exploration, development, and utilization. Participating delegates shared their accomplishments in the realm of shale oil and gas exploration and development technologies, engaging in profound discussions and fruitful exchanges on these subjects.