Geological conditions for oil and gas accumulation in Shuangyang Basin, Jilin province
LIANG Ben-ying1, LIU Yu-mei2, ZHOU Xin-gui3, LI Shi-zhen3, DONG Qing-shui1,4, LIU Wei-bin3, ZHANG Wen-hao3
1. College of Earth Sciences, Jilin University, Changchun 130061, China;
2. College of Applied Technology, Jilin University, Changchun 130022, China;
3. Oil and Gas Survey, China Geological Survey, Beijing 100083, China;
4. Key Laboratory for Oil Shale and Coexistent Energy Minerals of Jilin Province of Jilin University, Changchun 130061, China
Field geological surveys, interpretation of seismic sections and Shuangcan 1 drilling data show that the dark mudstone of the Lower Cretaceous Chang'an Formation in Shuangyang Basin of Jilin province is widely distributed, with stable thickness and high organic matter content. The organic matter type is mainly ��1 type kerogen, the organic matter evolution is at the mature level, and with better hydrocarbon-generating potential. It is considered to be the favorable source rock formation for good-best source rocks in Shuangyang Basin. Additionally, the dark mudstone of the Middle Permian Fanjiatun Formation which is widely distributed in the basement of the basin has good gas-generating potential. Fan-delta unconventional tight reservoir sand bodies were developed in the Chang'an Formation, while medium-acid volcanic structures with certain reservoir properties were developed in the Anmin Formation and Jinjiatun Formation. Favorable self-sourcing and self-reservoiring, lower-sourcing and upper-reservoiring, upper-sourcing and lower-reservoiring assemblages were formed. Together with the secondary uplift in the central part of the basin, a favorable central oil and gas accumulation zone with certain exploration prospects was formed.