渤东凹陷东南斜坡构造变换带识别及其石油地质意义

根据渤东凹陷斜坡带新钻井以及新采集的三维地震等勘探资料，采用构造样式解剖、断裂分析以及油气成藏规律分析等方法研究构造变换带特征及其石油地质意义。结果表明，渤东凹陷东南斜坡带上存在构造变换带，此变换带具有调节局部构造变形和分割构造带的作用，把斜坡带分割为西、中、东3个整体呈NE向的似花状构造带。变换带对于明下段极浅水三角洲沉积体展布具有一定控制作用，是砂体形成岩性尖灭的有利场所，同时，近SN向变换断层对NEE向断裂的封堵易形成构造圈闭、构造—岩性圈闭，具有较大的勘探潜力。3个似花状构造带的南部3条断层的断面与地层呈顺向配置，形成断面汇聚脊到顺向地层的优势运移路径，同时受到南部呈雁行排列的密集断裂带的阻挡，形成了研究区一条似花状构造内部的优势运聚范围，最终在渤东凹陷东南斜坡带上形成密集断裂带横向遮挡的主控断层—地层产状耦合油气富集模式。

IDENTIFICATION OF STRUCTURAL TRANSFER ZONES ON SOUTHEAST SLOPE OF BODONG SAG AND ITS IMPLICATIONS FOR HYDROCARBON ACCUMULATION

Based on newly acquired drilling and 3-D seismic data, the forming mechanism of the flower-like structural zone on the southeast slope of the Bodong Sag is studied and the mechanisms of hydrocarbon accumulation summarized through comprehensive analysis of structure styles and fault features as well as their relationship with hydrocarbon migration and accumulation. Results show that there are several structural transfer zones on the southeast slope of the Bodong Sag. They play a part of role in adjusting the local tectonic deformation and could be used as a clue to divide structural belts. The structural transfer zones may divide the slope belt into three similar flowerlike structure tectonic belts, i.e. the west, central and east, all extending in northeast direction. The structural transfer zones control the formation and distribution of the shallow-water deltaic body of the Lower Member of the Minghuazhen Formation, and are the favorable locations for pinching-out of sand bodies. NEE-strike faults may be blocked by SN transfer faults and form structural traps and structural-lithologic traps which have great exploration potential. The three faults to the south of the three flowerlike structural belts may provide favorable pathways for oil and gas migration and accumulation. Furthermore, in the south, the dense fault zones in en echelon pattern may obstruct the oil and gas migration. Based on the above-mentioned factors, an oil and gas accumulation model is proposed in this paper.