马朗凹陷芦草沟组页岩油流体压力与初次运移特征

摘要

通过源岩内流体压力特征分析、地球化学分析和岩心、岩石薄片观察等方法,对马朗凹陷芦草沟组页岩油的初次运移特征进行分析.结果表明:马朗凹陷芦草沟组虽然基质孔隙小,但孔隙度并不很低,是油气储集的主要空间,石油为源内自生自储,极好的源岩层又是产油层；芦草沟组页岩油是烃源岩在低成熟-成熟早期阶段生成的,由于源岩层渗透性较差,油气不具备大规模向外排运的条件而滞留在源岩层中未发生大规模排烃,仅断裂带附近芦草沟组烃源岩生成的石油向外排运明显,大部分地区页岩油只有源内小尺度的初次运移,并且其中的云质岩外来烃最明显；源岩内大量石油滞流是超压形成的主要原因.%On the basis of the analysis of the fluid pressure and geochemical characteristics as well as observing the core and thin sections, the characteristics of the shale oil primary migration were studied. The results show that the porosity of Lucao-gou formation is not too small and it is the main reservoir space for hydrocarbons although the matrix pore of Lucaogou formation is small in the Malang sag. The oil is self-generating and self-reserving in the source rock, so the good source rock itself is also the reservoir. Moreover, the shale oil of Lucaogou formation is a kind of low-mature oil, which is generated in the low-threshold mature stage. As a consequence of the poor permeability of the source rock, the oil can not migrate out of the source rock on a large scale and only near the fault. Usually it has a small scale primary migration in most areas, and the do-lomitic rock has the most obvious foreign hydrocarbons. Besides, the massive oil retention is the main reason of overpressure formation.