南阳凹陷层序地层学研究

A study of sequence stratigraphy at Nanyang depression

中国石化河南油田分公司勘探开发地质研究院,河南南阳 473132

Institute of Exploration and Development Research Henan Oil Company, SINOPEC, Nanyang 473132, China

通过对南阳凹陷层序地层的研究,综合应用地震、测井、岩心及其它分析化验结果,划分出一级层序界面3个、二级层序界面3个、三级层序界面7个。针对该区主要目的层核桃园组,在三级层序内又进一步细分为多个高频层序单元,且把其分别归属到低位域、湖扩展域和高位域等3种不同的沉积体系域内。结合该凹陷沉积体系的空间变化规律及凹陷演变过程中的构造变化,建立了南阳凹陷的层序构成模式,明确指出南阳凹陷南部断坡带和北部弯折带控制的低位域区为南阳凹陷寻找低位域砂体或隐蔽岩性油气藏的有利目标区。经实钻验证,新增控制地质储量超过500×10⁴t。

In the study of high resolution sequence stratig-raphy at Nanyang depression, we have identifiedthree boundaries of the first-class sequence, threeboundaries of the second-class sequence, and sevenboundaries of the third-class sequence. In the targetinterval of Taoyuan formation, more sequence unitsare identified in the third-class sequence. and tied to3 system tracts: HST (high system tract), LST(lower system tract) and EST (expanded systemtract), respectively. The sequence configuration ofthe Nanyang depression is established according tothe spatial variability of the sedimentary system andthe tectonic changes in the course of depression evo-lution. It is concluded that the LSTs at the southernfaulted ramp and the northern deflected zone in Nan-yang depression are favorable areas for subtle lithol-ogical reservoirs. Drilling demonstrates that the new-ly increased probable reserves exceed 500×10⁴ t.