渤海湾盆地廊固凹陷杨税务潜山带地质结构与构造演化

Geological structure and tectonic evolution of Yangshuiwu buriedhill belt in Langgu Sag, Bohai Bay Basin

杨税务潜山带位于渤海湾盆地廊固凹陷东部的河西务构造带内,整体呈NE向展布,由3个平行斜列的潜山组成,属于典型的断块掀斜型潜山,经历多次构造运动的改造作用,地质结构复杂。目前对杨税务潜山带形成演化过程研究程度较低,因而厘定杨税务潜山带的构造演化阶段有助于分析构造对油气运移、储层改造以及油气成藏的控制作用,为后续进一步明确有利勘探方向奠定基础。本次研究通过研究区内的钻井和地震资料,对杨税务潜山带的断层发育、构造层的划分进行了详细研究;运用平衡剖面技术揭示了杨税务潜山带的构造演化过程。结果表明,研究区共发育6套构造层,即:基底构造层、中—新元古界构造层、下古生界构造层、石炭—二叠系构造层、古近系构造层和新近系—第四系构造层。构造演化分析结果表明:印支期,在SN向挤压应力的作用下,杨税务地区形成了近EW向的古隆起;燕山运动中,古隆起发生旋转并抬升遭受剥蚀;在喜马拉雅期发生构造反转,大兴断层的强烈活动使廊固凹陷进入断陷阶段,随着河西务断层的发育,古隆起被分割为杨税务潜山和泗村店潜山两部分,位于下盘的杨税务潜山被拉断成如今3个潜山平行斜列的潜山带。本次对杨税务潜山带地质结构、构造演化以及构造的控藏作用的研究,为后续类似隐蔽型潜山油气藏研究提供了案例与参考。

Yangshuiwu buried hill belt is located in Hexiwu structural belt in the east of Langgu Sag,Bohai Bay Basin. It was distributed in NE direction and consists of three parallel buried hills. It is a typical fault block buried hill. It has undergone multiple tectonic movements and has a complex geological structure. At present,the research on the formation and evolution process of Yangshuiwu buried hill belt is relatively low. Therefore, determining the structural evolution stage of Yangshuiwu buried hill belt is helpful to analyze the control role of structures on oil and gas migration,reservoir reconstruction and oil and gas accumulation,and lays a foundation for further defining the favorable exploration direction. We used the drilling and seismic data in the study area to research the fault development and structural layer division of Yangshuiwu buried hill belt in detail. The structural evolution process of Yangshuiwu buried hill is revealed by using the balanced profile technique. The results show that 6 sets of structural layers are developed in the study area:basement structural layer, Meso-Neoproterozoic structural layer, Lower Paleozoic structural layer,Carboniferous-Permian structural layer,Paleogene structural layer and Neogene Quaternary structural layer. The results of tectonic evolution show that: in Indosinian Period,under the action of SN trending compressive stress, the Yangshuiwu area formed an EW trending paleo uplift.During the Yanshan movement,the ancient uplift rotated and uplifted and suffered denudation.The tectonic inversion occurred in the Himalayan Period,and the strong activity of Daxing fault made Langgu Sag enter the fault depression stage. With the development of Hexiwu fault,the ancient uplift was divided into Yangshuiwu buried hill and Sicundian buried hill. Yangshuiwu buried hill located in the footwall was pulled and broken into a buried hill belt with three buried hills in parallel. This study on the geological structure,structural evolution and structural reservoir control of Yangshui buried hill belt provides a case and reference for similar concealed hill reservoirs in the future.