关键词: 渤海湾盆地, 鄂尔多斯盆地, 上古生界, 自生自储成藏, 二次生烃, 天然气成藏条件

Abstract: Analysis of some important factors for forming gas pool such as source rock, reservoir rock, cap rock and trap in the Upper Paleozoic of Ordos Basin and Bohai Bay Basin shows that the two basins are both favorable to form the self-source and self-reservoir gas pools with a complete combination of source rock, reservoir and cap rock. The timing matching relation between the pool-forming factors shows that Ordos Basin is characteristics by single embedding-uplifting episode, continuous hydrocarbon generation and early gas accumulation, while Bohai Bay Basin is characteristics by multiple embedding-uplifting episode, secondary hydrocarbon generation and late gas accumulation. The spatial matching relation of pool-forming factors shows that the Upper Paleozoic in Ordos Basin has timing, vertical and lateral continuity of resource rock, reservoir rock and cap rock. So it has good preserving condition for natural gas and can form big lithologic gas pools distributed in great area. Ordos Basin has a great potential of natural gas resources. Natural gas in Bohai Bay Basin needs vertical migration with a great altitude to become reservoir. Bohai Bay Basin with a limited superposing area of secondary hydrocarbon generating zone and structural accumulation zone in high part can only form structural gas pool with moderate-small size and high gas abundance.

Key words: Bohai Bay Basin, Ordos Basin, the Upper Paleozoic, self-source and self-reservoir pool formation, secondary hydrocarbon generation, gas pool-forming condition