渤海海域低熟油特征及发育前景: 以辽西南洼为例
摘要
Organic geochemical analysis in Bohai Sea area of Bohai Bay Basin reveals that low-mature oil and gas are widely found in some structural belts, but the genesis and resource potential of low-mature oil and gas have been ignored and not systematically studied.Taking Liaodong Bay Depression as the research object, the characteristics of low-mature oil are systematically analyzed in combination with different structural unit reservoirs, and the potential and prospect of low-mature oil and gas generation from source rocks are studied.The results show that: (1) Low-mature oil is developed in the Liaodong Bay Depression.The reservoirs in the steep slope belt of South Liaoxi Depression are characterized as belonging to the typical low-mature oil reservoir, with the characteristics of the high density, high acid value, high colloid and high asphaltene, odd-even obvious advantages, and the C 14 -C 16 sesquiterpenes series are complete, with higher gammacerane index.It is obviously different from the reservoirs in the Liaoxi uplift belt and the Liaozhong Depression, immature oil mainly source from saltwater lacustrine source rocks in South Liaoxi Depression.(2) The saltwater source rocks have unique characteristics of double peak hydrocarbon generation, and a large amount of liquid hydrocarbon rich in colloid and asphaltene is generated in the low mature evolution stage, which has rich potential and broad prospects of low mature oil resources.