南襄盆地唐河低凸起地质结构与勘探潜力

Geological Structure and Exploration Potential of Tanghe Low Uplift in Nanxiang Basin

唐河低凸起是南襄盆地内分隔泌阳凹陷与南阳凹陷的次级正向构造单元,其地质结构研究对该区油气勘探和分析泌阳、南阳两富油凹陷的构造沉积充填关系均具有重要意义。以地震、钻测井及地化资料为基础,分析唐河低凸起的地层充填、构造特征、形成演化和成因机制,并探讨其油气勘探潜力。研究表明,唐河低凸起自下而上发育玉皇顶组、大仓房组、核桃园组、凤凰镇组及平原组。构造东西分块,为受桐河街断层分隔的南阳、泌阳两凹陷斜坡带组成的“类地垒”形态;南北分带,呈多个半地堑形态。构造演化分析将该区演化阶段划分为统一沉降期、差异沉降期、挤压定型期和拗陷期4个阶段,低凸起的成因机制与区域构造应力场转换下边界断层的差异活动密切相关。唐河低凸起具有多凹陷烃源岩供烃、多层系有效储层发育、长期高效输导体系及多类型圈闭垂向叠加的有利条件,具有一定的油气勘探潜力。

Tanghe Low Uplift is a secondary positive structural unit separating Biyang Depression and Nanyang Depression in Nanxiang Basin.The study of its geological structure is of great significance to the exploration of petroleum in this area and to the analysis of the structural-sedimentary filling relationship between Biyang and Nanyang oil-rich depressions.Based on seismic,well logging and geochemical data,we analyzes the stratigraphic distribution,structural characteristics,formation and evolution,genetic mechanism of Tanghe Low Uplift,and discusses its petroleum exploration potential.The results show that the strata developed from the bottom to the top are Yuhuangding Formation,Dacangfang Formation,Hetaoyuan Formation,Fenghuangzhen Formation and Pingyuan Formation.The structure is divided into East and West blocks,which is a “Horst like” structure composed of slope zones of Nanyang and Biyang depressions separated by Tonghejie Fault;the structure is divided into North and South zones,in the form of multiple half grabens.According to the balanced geological section,the tectonic evolution of the area is divided into four stages,namely,the unified subsidence stage,the differential subsidence stage,the compression setting stage and the depression stage.The genetic mechanism of low uplift is closely related to the differential activities of boundary faults under the transformation of regional tectonic stress field.Tanghe Low Uplift has favorable conditions for hydrocarbon supply of multiple sags,effective reservoir development of multi-layer system,longterm and high-efficient transport system,vertical superposition of multiple types of traps,and has great petroleum exploration potential.