太阳集团网tyc9728(百度)有限公司

This study systematically investigates the genesis, migration, accumulation, and distribution patterns of natural gas and CO2 in the Changling Fault Depression of the Songliao Basin through an interdisciplinary Earth system framework, focusing on multi-sphere interactions. Integrated analyses employing gas geochemistry, numerical simulations, and core observations reveal that deep magmatic-hydrothermal processes (lithosphere) provide the primary heat and fluid sources, paleoclimate oscillations (atmosphere) modulate organic productivity and preservation efficiency, and lacustrine-level fluctuations (hydrosphere) control reservoir connectivity and gas-phase partitioning. These synergistic controls jointly determine hydrocarbon generation in source rocks, volcanic reservoir evolution, and CO2-CH4 competitive accumulation. Results indicate that natural gas within the Changling Fault Depression is predominantly thermogenic with localized abiotic contributions, as evidenced by δ13C1 values ranging from −56.8‰ to −1.7‰ and the coexistence of both normal and reversed carbon isotopic fractionation sequences. CO2 exhibits a dominant inorganic mantle-derived origin, characterized by δ13CO2 values between −18.9‰ and −0.6‰. Thermogenic gas preferentially accumulates in volcanic reservoirs of the Quantou and Yingcheng Formations, while CO2 and CH4 display planarly complementary distributions, with high-CO2 concentrations localized in the eastern Changshen area corresponding to low-CH4 zones. Paleoenvironmental reconstructions reveal a progressive transition from deep to shallow lacustrine conditions, from humid to semi-arid climate regimes, and from freshwater to brackish depositional environments during the Early Cretaceous. Source rocks of the Shahezi Formation exhibit stronger primary productivity and higher hydrocarbon generation potential than those of the Yingcheng Formation, driven by coupled effects of tectonic subsidence, volcanic nutrient input, and redox-controlled organic preservation. Tectonic evolution governs vertical hydrocarbon migration and mantle-derived CO2 influx through volcanic activity and fault system development, whereas climate-sedimentation coupling under Ferrel circulation and global eustatic cycles regulates organic matter enrichment. This integrated analysis establishes a comprehensive framework for volcanic gas reservoir exploration and CO2 geological sequestration, contributing to the synergistic advancement of carbon neutrality and energy security strategies.