In the heart of Jiangxi Province, China, a groundbreaking study is reshaping the future of salt cavern storage, a critical component in the nation’s quest for carbon neutrality. Led by Dongming Liu from the State Key Laboratory of Deep Earth Exploration and Imaging at the Chinese Academy of Geological Sciences, the research published in *Meitian dizhi yu kantan* (translated as *Modern Geology and Prospecting*) is unlocking new efficiencies in selecting optimal sites for salt cavern storage, a game-changer for the energy sector.
Traditionally, the siting of salt cavern storage facilities has relied heavily on drilling and coring, methods that are not only costly but also fall short in assessing the vertical continuity of salt rock formations. “These traditional methods have been bottlenecks in our quest for efficient and precise geological evaluation,” Liu explains. His team’s innovative approach integrates multiparameter geophysical logging with geological records of cores, offering a more comprehensive and accurate assessment of salt-bearing strata.
The study focused on borehole ZK01 at the Qingjiang Salt Mine, a site pivotal for the preliminary feasibility study of salt cavern storage. By analyzing the structural characteristics of salt-bearing strata, Liu’s team identified key parameters such as ore-bearing coefficient, ore grade, interlayer distribution, and the properties of roof, floor, and cap rocks. The results were striking. The salt rocks exhibited distinct log responses, characterized by low gamma-ray values, low sonic interval transit time, low compensated neutron log values, and high three lateral resistivity. In contrast, mudstones showed opposite trends, with high gamma-ray values, high compensated neutron log values, high sonic interval transit time, and low three lateral resistivity. Transition rocks displayed a gradational trend in their petrophysical property parameters.
One of the most significant findings was the enhanced lithological identification efficiency achieved through GR-CNL cross plots. This method allowed for semi-quantitative identification of four lithologies, a substantial improvement over traditional curve overlapping and reconstruction methods. The interval between 906 meters and 1,095 meters was identified as the optimum target horizon for salt cavern storage, boasting an ore-bearing coefficient of 51.1%, an average NaCl grade of 69.46%, and other favorable characteristics.
The implications of this research are profound for the energy sector. Salt cavern storage facilities are key infrastructure for clean energy strategic reserves, playing a crucial role in the transformation and upgrade of the salt industry and the building of a low-carbon energy system. Liu’s methodology provides a more efficient and precise way to evaluate geological conditions, reducing costs and improving the accuracy of site selection. “This technique enables the quantitative characterization of the structural characteristics and mineral assemblages of salt-bearing strata, providing key geological parameters and a basis for scientific decision-making,” Liu states.
The study’s findings are particularly relevant for regions with high tectonic stability and simple mineral assemblages. However, Liu cautions that for areas with complex geological settings, adaptive optimization using high-resolution logging techniques may be necessary. This nuanced approach ensures that the methodology remains robust and applicable across diverse geological landscapes.
As China and the world strive to meet carbon emission goals, the need for efficient and reliable energy storage solutions has never been greater. Liu’s research offers a promising path forward, one that could significantly impact the energy sector’s ability to meet these challenges. By providing a more accurate and cost-effective means of selecting optimal sites for salt cavern storage, this study is paving the way for a more sustainable energy future.
In the words of Liu, “This methodology proves universally applicable to salt-bearing basins with high tectonic stability and simple mineral assemblages.” As the energy sector continues to evolve, the insights gained from this research will undoubtedly shape future developments, driving innovation and progress in the quest for clean energy solutions.