渤海郯庐走滑断裂带新生代差异变形及其油气成藏效应

The Tanlu strike-slip fault which traverses the eastern side of the Bohai Bay basin exerted important influences on structural deformation, evolution and hydrocarbon accumulation in the basin. This project aims to analyze the Cenozoic differential deformation of the Tanlu strike-slip fault and its significances on hydrocarbon accumulation in the offshore Bohai Bay basin. Firstly, based on the interpretation of 3D block-jointed seismic data and structural mapping, the deformation and distribution features of the Tanlu fault will be addressed. And then, the models of differential deformation will be created. Secondly, 3D balanced reconstruction and apatite fission track dating, which are helpful for studying evolution history of the Tanlu fault, will also be completed in this project. Thirdly, The formation processes of some typical structural styles of the Tanlu strike-slip fault will be reappeared by physical modelling, which will also be used to investigate dynamic factors controlling the activities of the fault.Through analyzing the interaction of faults in special areas along the Tanlu strike-slip fault, such as the bending, intersecting and overstepping areas, the strike-slip transfer zones will be modelled. At last,combining the structural analysis of several giant oil and gas fields along the Tanlu strike-slip fault, this project will indicate the significances of the differential deformation of the Tanlu strike-slip fault on hydrocarbon accumulation,and establish related formation models of hydrocarbon accumulation. The comprehensively study on　the Cenozoic differential deformation of the Tanlu strike-slip fault and　its influences on hydrocarbon accumulation in the offshore Bohai Bay basin not only can enrich the domestic research on strike-slip faults, but also contribute to a deeper understanding of oil and gas distribution in this area. As result, this project has scientific significances and practical guidance roles.

通过对渤海东部郯庐走滑断裂带沿线高品质连片三维地震资料进行精细解释，对比分析郯庐断裂带的剖面变形及平面展布特征，建立断裂带分段、分带差异变形模式；利用三维构造平衡复原和磷灰石裂变径迹定年测试结果，分析郯庐断裂带活动演化历史，划分断裂活动期次；通过构造物理模拟实验，恢复典型构造变形样式形成过程，明确影响郯庐断裂带形成演化的动力学因素，建立断裂带形成演化动力学模型；通过分析郯庐断裂带拐弯、合并和叠置等部位的断裂相互作用特征，建立走滑型构造变换带发育模式，并结合典型油气田构造特征解剖结果，分析郯庐断裂带差异变形对油气聚集成藏的影响，最终建立受断裂带差异变形作用控制的油气聚集成藏模式，为油气富集区带的优选提供科学依据。本研究不仅可以丰富我国走滑断裂构造研究内容，而且还有助于深入了解渤海地区油气富集规律及其控制因素，具有重要的科学意义和实践指导作用。

从渤海东部地区通过的郯庐走滑断裂带对盆地地质结构和形成演化以及油气成藏等都产生了重要影响，对郯庐断裂带新生代变形特征及其油气成藏效应开展研究不仅可以丰富我国走滑断裂构造研究内容，而且还有助于深入了解渤海地区油气富集规律及其控制因素，具有重要的科学意义和实践指导作用。本项目通过对渤海东部郯庐走滑断裂带沿线高品质连片三维地震资料进行精细解释，建立了断裂带的分带、分段差异变形模式。渤海郯庐断裂带展布范围从北向南逐渐增大，可划分为北部的辽东湾段、中部的渤东段和南部的渤南段，其中辽东湾段包括南部压扭段和北部凸起段，北部凸起段还可进一步细分为复合凸起段、隐伏凸起段和单一凸起段。构造平衡复原结果表明，郯庐断裂带辽东湾段表现出早段早衰的活动特征，而渤东段和渤南段分别具有中断晚衰和早断晚衰的活动特征。磷灰石裂变径迹定年测试结果也表明，郯庐断裂带的走滑活动引起渤海东部地区在中、新生代发生了多次构造隆升，分别是87Ma（晚白垩世）、54 Ma（古新世末）和37-23 Ma（渐新世末），其中24Ma时全区普遍有一次构造抬升活动，但在不同地区的持续时间和强度有所差别。物理模拟实验证实，南北向伸展作用在渤海地区新生代构造变形过程占主导地位，郯庐断裂带新生代右行走滑作用是南北向伸展作用在早期基底断裂之上所导致的斜向走滑运动，具有一定“被动”性质。郯庐断裂带平面变形宽度自北向南逐渐增大也与不同部位基底走滑断裂和应力夹角的差异有关。郯庐断裂带的走滑活动导致渤海东部地区辽东凸起和渤东低凸起等双断式凸起的形成，而且对早期伸展断裂体系产生了改造作用。郯庐断裂带的S型转换作用、叠覆型转换作用和联接型转换作用控制了大型圈闭群的发育，局部压扭应力场背景下的断背斜类圈闭是比较有利的勘探目标区。