廊固凹陷大兴断层对油气分布的控制研究

RESEARCH ON THE HYDROCARBON DISTRIBUTION CONTROLLED BY DAXING FAULT IN LANGGU SAG

廊固凹陷断裂系统复杂,其中大兴断层是中西部的控盆边界断层,它通过对凹陷的构造样式、沉积特征的控制进而影响整个凹陷的油气分布。从区域构造背景和盆地的沉积演化角度,按不同段落断裂展布的方向、产状的陡缓、对沉积的控制作用以及不同层段物质组份的差异,将大兴断层划分为4段:北段、中北段、中南段和南段,各段又可进一步分为上下不同的两段。各段断层的结构、形态、伴生构造、活动时间等都存在较明显差异,通过控制物源而控制沉积相的展布、储层物性和生储盖组合。相应的伴生构造和沉积物发育特征导致构造、构造—岩性组合控制了油气的分布:北段下段、中北段下段近湖一侧是廊固凹陷中西部有利的油气聚集带;中北段上段发育的生物气藏具有一定的勘探前景。

With a complicated cracking system, Daxing fault in Langgu sag controls the mid-west edge and influences the whole hydrocarbon distribution in the sag through the structure pattern and sedimentary characteristics. Starting from the regional structure background and sedimentary evolvement, according to the extending trends, steep or slow of attitude, function of controlling sediment and material constituent in the different segments, the fault is divided into four segments: i.e. north segment, mid-north segment, mid-south segment and south segment, then each one can be divided into two sects. Each segment has different framework, conformation, associated tectonic, activity time and controls sedimentary extending trends, reservoir physical property and source-reservoir-cap assemblage by diverting material source. The relevant associated tectonic and sediment development characteristics made the structure and structure-lithology combination controlling the hydrocarbon distribution. The near shore side of the lower parts of north and mid-north segments is favorable to the hydrocarbon enrichment in the mid-west part of Langgu sag and the biology gas pole locating the upside of mid-north segment is of a certain exploration prospects.