渤海湾盆地济阳坳陷东部走滑构造特征及其对油气成藏的影响研究

研究区位于郯庐断裂中段与济阳坳陷的构造结合部，区内走滑构造广泛发育，主要的走滑断裂有7条，分别是郯庐断裂带的东西两支、垦东断层、孤东断层、长堤断层、埕东断层和发育于垦东凸起中部的浅层走滑构造带。走滑构造带与油气富集带有着明显的对应关系。 通过对研究区内二维、三维地震测线和平面构造图的精细解释和分析，分别揭示了各走滑断裂在平面、剖面和三维空间上的构造形态。根据走滑断裂及其伴生构造的平面和剖面上的几何学特征，将研究区内的走滑断裂划分为三种类型：成熟型走滑断裂、隐伏型走滑断裂、不连续型的走滑断裂。 从理论模式研究入手，推导了拉分盆地中盆地的走滑速率与沉降速率之间的关系，证实了走滑速率同盆地的几何形状参数、最大沉降深度和盆地的沉降速率存在着稳定的数值关系。通过对莱州湾地区潍北凹陷基底沉降历史的分析，建立了潍北凹陷沉降速率与郯庐断裂中段走滑速率之间的经验关系式，进而求出郯庐断裂中段新生代右行走滑位移量的大小为40km。 运用2DMove软件，对研究区内四条典型剖面进行构造复原，计算出了各条剖面每个时期的伸展参数，对研究区构造活动强度进行了定量分析，揭示了研究区的构造演化规律。通过运用Ansys软件进行有限元模拟，恢复了晚白垩世晚期-古近纪早期研究区内的构造应力场和应变场，揭示了扭张作用是研究区内走滑断层开始走滑的主要原因。 通过上述分析，结合对究区内近几年勘探开发成功和失败的实例分析，全面探讨了走滑活动对于油气成藏“生”、“储”、“盖”、“圈”、“运”、“保”各因素的影响。

The study area is located in the conjunction area of Middle Tan-Lu fault zone and Jiyang depression. Strike-slip structures are greatly developed. There are seven main strike-slip faults in the study area: East and West branch faults of Tan-Lu fault zone, Kendong fault, Gudong fault, Changdi fault, Chengdong fault and shallow strike-slip fault zone developed in the middle part of Kendong uplift. Strike-slip structural zones coincide with oil&gas accumulation zones in the study area. Based on the interpretation results of 2D and 3D seismic profiles and structural maps, the horizontal, vertical and spatial strucutural features of the main strike-slip faults are studied. According to their horizontal and vertical features, they are divided into three types: matured strike-slip fault, buried strike-slip fault and discontinuous strike-slip fault. On the basis of theoretical model research, the formula between the strike-slip rate and the subsidence rate in the pull-apart basin is derived. It is confirmed that the strike-slip moving rate has a steady relationship with the geometric parameters, max subsidence depth and the subsidence rate of the strike-slip basin. Based on the subsidence history analysis of the Weibei sag, the experiment relation between the Tan-Lu fault strike-slip rate and Weibei sag subsidence rate is obtained and the Cenozoic dextral strike-slip displacement of the Middle Tan-Lu fault in the Laizhou Bay is calculated for about 40km. Four typical seismic profiles in the study area are restored using 2DMove software. The extension parameters of every balanced cross-section in the different period are calculated.The intensity of tectonic evolution is quantitatively analyzed and the tectonic evolution history is revealed. The structural stress field and strain field of the study area during the late Late-Cretaceous to early Tertiary are rebuilt after finite element analysis using Ansys software. The results show that the transtension in study area at that time is the main reason for the trigger of the strike-slip faults strike-slipping movement. Based on the above analyses, together with the successful and failing oil&gas exploration and development cases during the recent year in the study area, the influence of the strike-slip movement on the important oil&gas accumulation factors: source rock, reservoir rock, cap rock, migration pathway, trap and preservation is carefully studied.