Against the backdrop of global low-carbon energy transition, the green, economical, and efficient development of shale oil and gas resources faces a series of challenges in theoretical frameworks, technological costs, low-carbon innovation, and engineering management. To foster technological independence and advance low-carbon development through academic exchange, the 6^th International Symposium on Shale Oil and Gas Exploration, Development, and Utilization Technology was held by Jilin University in Changchun, China, from November 7 to 9, 2025. This symposium gathered over 270 experts and scholars from more than 50 institutions worldwide featuring 61 presentations spanning geological theory, intelligent exploration, drilling and completion technologies, in-situ conversion, pyrolysis mechanisms, enhanced recovery, and low-carbon strategies. The discussions underscored a decisive shift towards intelligent, integrated, and green technological solutions, highlighting the critical role of artificial intelligence, nanotechnology, and carbon management in field advancement. This event significantly strengthened the industry-academia-research-application collaboration system, providing important momentum for achieving technological independence and driving the shale industry towards a sustainable and secure energy future.

China’s oil shale resources contain about 47 billion tonnes of shale oil, and its large-scale exploitation will effectively alleviate the current oil and gas supply situation in China. In-situ conversion, which is the trend for exploiting oil shale resources, has not yet been commercialized due to the limitations of technical difficulty and high cost. In response to the characteristics of China’s oil shale resources, some universities, research institutes and energy companies have developed a variety of in-situ conversion technologies. Among them, Jilin University and Jilin Zhongcheng Oil Shale Company have constructed three pilot tests in the Songliao Basin, all of which have successfully produced shale oil from underground verifying the feasibility of the in-situ conversion technologies to a certain extent. However, there are still some issues of in-situ conversion technologies, such as low technology maturity, small test scale, high cost and low oil and gas recovery. With the background of the energy demand and the Dual Carbon Targets in China, the in-situ exploitation of oil shale faces both opportunities and challenges, calling for prompt action in the areas of efficient compound heating, reservoir stimulation, cost reduction and efficiency enhancement, low-carbon sustainable development, etc. At the same time, guidance from national policies and cooperation among industry, university and research institutes serve as essential measures to facilitate the commercialization of oil shale in-situ exploitation.

In-situ conversion is essential for the development of oil shale resources. Reservoir blockage has been confirmed to be a technological bottleneck via laboratory-scale experiments and field tests. This issue arises from the precipitated asphaltene and its thickening effect on the pyrolysis oil. Promoting in-situ secondary cracking of asphaltene has the potential to mitigate blockage. However, the secondary cracking characteristics of asphaltene have not yet been determined. In this study, asphaltenes were obtained under different pyrolysis temperatures, atmospheres and duration times, their secondary cracking mechanisms were investigated. These findings demonstrate considerable mass loss and discrepant reaction processes across different asphaltenes. Firstly, the mass loss of asphaltenes exceeds 80% at 500 ℃ for all the samples, and the released space can restore reservoir permeability. Second, based on the evolution of the activation energies and pyrolysis gas components, the asphaltenes obtained under severe conversion conditions undergo pyrolysis defined by synchronous two-stage reactions, whereas the asphaltenes obtained under mild conversion conditions undergo pyrolysis defined by sequential three-stage reactions. Finally, a method for eliminating reservoir blockage was proposed based on the above theories, involving inhibiting asphaltene migration and promoting its in-situ secondary cracking by controlling the parameters of the heat-carrying fluid, thereby achieving an unaffected reservoir or reservoir self-unblocking. The obtained results can provide valuable references for the in-situ exploitation of oil shale.

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.