不整合面输导体系研究——以中国南海Q盆地深水区古近系L组为例

Research on Unconformity Surface Pathway System——Taking L Formation of Paleogene in Deepwater Area in Q Basin in South China Sea As An Example

针对中国南海Q盆地深水区古近系L组的地质实际,主要利用地震资料对4个三级层序界面上的不整合面输导体系特征进行了详细研究。结果发现,不整合面为该区油气运移输导的主要路径。发育在盆地或凹陷边部的大地层倾角的角度不整合面主要对油气的垂向运移起作用,而发育在盆地或凹陷中心部位的平行不整合面,特别是那些大面积分布的平行不整合界面,对油气的侧向运移输导起主要作用,上述两类不整合面的有机组合完成了油气在时空上的大范围运移输导。结合沉积相展布特征、断层发育特征及烃源岩发育特征,研究发现深水区L组优势运移通道主要发育于凸起边缘不受断层封堵的连片不整合面处,而与这些优势输导体系相连的扇三角洲、斜坡扇、盆底扇、浊积扇及滩坝是油气勘探的有利区域。

Aimed at the geological status characteristics of Paleogene L Formation of Q basin in South China Sea,traversed characteristics of unconformity surface pathway system was divided in to 4 third class sequences boundary by using seismic date.The results show that unconformity surface pathway system becomes mainly way of oil and gas migration.That angle unconformity developed at the edge of basin or depression play an important role in the process of petroleum migration in the upright direction,and the parallel unconformity developed in the center of the basin or depression,and especially developed at large-scale play an important role in the process of petroleum migration in the landscape orientation.The two kinds of pathway systems completed the process of hydrocarbon large-scale migration by effective combination.Combined the characteristics of sediment and faults,superiority pathway systems mainly developed at the edge,which is blocked by the faults,and fan deltas,slope fan,basin floor fan,turbidite fan,beach bar connected with superiority pathway system are favorable prospecting area.