北部湾盆地涠西南凹陷与海中凹陷古近纪沉积关系探讨

涠西南凹陷与海中凹陷相邻,油气勘探成果及石油地质条件认识程度不同。通过对地层原始产状的恢复,讨论了涠西南低凸起对两凹陷古近纪沉积环境的阻隔作用,并对古新世和始新世沉积可容空间原型进行了恢复,认为古新世两凹陷局部连通,始新世和渐新世两凹陷全部连通;3号断层作为两凹陷区划边界的一部分,其活动强度控制了沉积可容空间的分布和容积的大小,始新世3号断层活动强度最大,其形成的沉积可容空间也最大,由于两凹陷沉积连通,因此两凹陷始新统生烃能力可以进行类比分析。

Discussion on Sedimentary Relationship between Weixinan Sag and Haizhong Sag during Paleogene Period in Beibuwan Basin

Weixinan Sag and Haizhong Sag is adjacent,but oil-gas exploration achievement and the understanding about petroleum geological conditions of both sags are different.By means of recovering original attitude of strata,influence of Weixinan low uplift on sedimentary environment of both sags during Paleogene was discussed and sedimentary accommodation space archetype was recovered during Palaeocene and Eocene.It’s believed that two sags were part connected during Palaeocene and fully connected during Eocene and Oligocene,and as part of boundary of the two sags,No.3 fault controlled the distribution and cubage of sedimentary accommodation space.Because the activity intensity of No.3 fault was maximum during Eocene,the sedimentary accommodation space was also maximum in Eocene.As these two sags were fully connected,an analogy can be drawn between hydrocarbon generation ability of Eocene strata in Weixinan Sag and Haizhong Sag.