苏北盆地高邮凹陷戴南组震积岩特征及其石油地质意义

Significance Research on Seismites Features and Petroleum Geology in Dainan Formation of Gaoyou Sag,Subei Basin

高邮凹陷戴南组沉积时期,在中—新生代构造运动的影响下,古地震活动强烈,岩层中发育了一系列与古地震有关的准同生变形构造。诸如液化岩脉、液化角砾岩、枕状层、环状层理及震褶层等液化挤压变形构造;又可见阶梯状断层、震裂岩、自碎角砾岩、内碎屑副角砾等脆性变形构造。另外,在岩芯观察的过程中发现,这些地震作用变形构造层往往与地震作用下的重力流沉积岩层相伴生,在此基础上通过总结区域联井和单井序列,刻画出了研究区震积岩的垂向序列。结合研究区油气成藏特征,从油气运移、储集和封堵三个方面对地震事件的油气地质意义进行了讨论,在此基础之上,提供了一个新的勘探方向,打破以往"环凹找油"的勘探思路,认为深凹带砂体也具有重要的勘探价值。

During the sedimentary period of Dainan Formation of Gaoyou sag, some ancient earthquake events were fiercely developed under the influence of Meso-Cenozoic tectonic movement. A series of quasi contemporaneous deformation structures related to earthquakes occurred in the strata, such as liquefaction extrusion deformation structure of liquefied rock veins, liquefied breccia, pillow beds, lamina circularis, seismo-folds and so on. Brittle deformation structure of step fault, shatter breccias, Self-broken breccia, internal debris breccia were also visible in the strata. In addition, these earthquake actions and deformation tectonic layers can be found on the cores to be always generated with turbidite stratum under earthquake action. The vertical sequence of earthquake rocks was described on the basis via summarizing single well and united wells sequences. Combined with hydrocarbon accumulation characteristics in the,study area, the significance of earthquake events was discussed in petroleum geology from three aspects, hydrocarbons transportation, accumulation and plugging. This research provided a new exploration direction, broken the previous exploration methods of “searching for oil around sags”, and consider the deep sag belt sand bodies to be also equivalent in exploration value.