渤海湾盆地与鄂尔多斯盆地成藏条件对比

Comparative studies of reservoir formed conditions of Bohai Bay and Ordos Basin

对比渤海湾盆地与鄂尔多斯盆地上古生界的油气成藏条件,二者在上古生界烃源岩厚度、有机质类型等方面差别不大,只是渤海湾盆地存在二次生烃,而鄂尔多斯盆地由于有机质演化程度较高,只有一次生烃;二者的上古生界储集层都属于低孔低渗类型,盖层对生成的油气都能起到很好的封盖作用,认为二者成藏模式十分相似。鄂尔多斯盆地的油气主要储集于岩性圈闭中,上古生界岩性油气藏在渤海湾盆地未来的勘探中值得关注。

A comparative study of Upper Paleozoic oil-gas reservoir formed conditions of the Bohai Bay and Ordos Basin shows that their patterns are very similar because there is little difference in thickness of source rocks and type of organic matter. Secondary hydrocarbon generation only occurred in the Bohai Bay Basin, while there only existed one in the Ordos Basin, NW China, due to high evolution of organic matter. Reservoirs in both basins are characterized by low porosity and low permeability, and oil and gas could be well sealed by the cap rocks, resulting in the formation of different types of oil-gas reservoirs. The oil and gas in Ordos Basin was mainly preserved in lithologic traps and the future plays of the Bohai Bay Basin should be focused on the Upper Paleozoic lithologic traps.