东庄次凹边缘断层坡折带对油气成藏的作用

为加深凹陷边缘断层坡折带对油气成藏作用的认识，运用层序地层学的原理对东庄次凹油气藏的分布及成因进行报分析。认为位于南阳凹陷东庄次凹北部边缘的东1层断层，在H2^2－H3^1层序发育期具有同沉积性质，形成了规模较大的凹陷边缘断层坡折带。该断层坡折带控制着低水位体系域的发育范围及层序的构成。坡折之上仅发育高位及湖侵体系域，且层薄，坡折之下地层厚度明显加大。在H2^2－H3^1层序低位域发育水下扇、盆底扇等，这些低位砂岩复合体直接插入较深湖相泥岩中，油源条件好，断层是良好的油气输导体系。断层坡折带是油气藏聚集的有利地带，也是陆相断陷盆地隐藏油气藏勘探的新领域。

Reservoir-forming Conditions in Fault Slope Break at the Margin of Dongzhuang Sub-depression

The No.1 growing fault, located near the northern margin of Dongzhuang sub-depression in Nanyang depression, had the characteristics of contemporaneous fault during the development of sequeace H_2 2-H_3 1 and formed a large scale fault slope break. It controlled the distributin of low-stand system tract and the construction of sequence. Only high-stand system tract and lake transgression system tract with small thickness developed above the fault slope break whereas the thickness of formations increased below the fault slope break.Fan deposits such as underwater fan and basin bottom fan that developed in the low-stand system tract of sequence H_2 2-H_3 1 cut directly into deeper mudstone of lake facies and had supreme source conditions with faults as good hydrocarbon conducting systems. The fault slope break is a favorable area of oil accumulation and new target of subtle reservoir exploration in terrigenous fault-depression.