泌阳凹陷东南部下切谷的发现及其意义

doi:10.11743/ogg20010404

摘要/Abstract

摘要：

通过对泌阳凹陷下第三系核桃园组层序地层学研究,于核三段二、四砂组发现两套下切谷沉积.该下切谷在地震剖面上为与上下相邻同相轴明显不协调的顶平底凹型,内部具充填结构特征;岩性粗,以含砾中粗砂岩为主,且与谷外红层和沼泽沉积明显区别;下切谷中Sr,P,Mn²⁺都处于异常高值,表明下切谷与底部地层间沉积环境存在一个突变过程.目前,仅在北部斜坡带的孙岗下二门地区发现了下切谷,垂向上分布于层序Ⅱ和层序Ⅲ低位域.陆相断陷湖盆中构造沉降作用很大程度上影响着下切谷的形成和充填,使下切谷在充填上表现为特殊的"顺源堆积"充填方式;湖侵期下切谷已被完全充填,下切谷顶面拉平面相当于初次湖泛面;下切谷内沉积特征和充填方式利于形成多种隐蔽圈闭.

关键词: 泌阳凹陷, 核桃园组, 下切谷, 层序边界, 初泛面, 隐蔽圈闭

Abstract:

According to sequence stratigraphic study,two sets of incised valley can be identified from Hetaoyuan Formation in the Southeast of Biyang Depression.The incised valley is clearly different from the around redbeds and marsh deposits on seismic profile,contains mainly conglomeratic coarse sandstone with abnormal high Sr,P and Mn²⁺ contents.This suggests that there had been a sudden change between the valley and the basement stratum.The valley is only found in Sungan Xiaermen area on the north slope of the depression,and distributed vertically in the lowstand system tract of sequencesⅡ and Ⅲ. The sedimentary characteristics and the filling manner are favourable for the formation of various concealed traps.

Key words: Biyang Depression, Hetaoyuan Formation, incised valley, sequence boundary, initial flooding surface, concealed trap

中图分类号:

TE121.3

鲜本忠,姜在兴,操应长,等. 泌阳凹陷东南部下切谷的发现及其意义[J]. 石油与天然气地质, 2001, 22(4): 304-308. doi: 10.11743/ogg20010404 Xian Benzhong,Jiang Zaixing,Cao Yingchang,et al. DISCOVERY OF INCISED VALLEY IN SOUTHEAST OF BIYANG DEPRESSION AND ITS SIGNIFICANCE[J]. Oil & Gas Geology, 2001, 22(4): 304-308. doi: 10.11743/ogg20010404

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