四川盆地万源—达州克拉通内裂陷的发现及勘探意义

发布时间：2018-02-27 11:39

本文关键词： 四川盆地川东北地区万源—达州震旦纪—早寒武世克拉通内裂陷岩相古地理构造运动　出处：《石油勘探与开发》2017年05期 　论文类型：期刊论文

【摘要】：随四川盆地震旦系—寒武系天然气勘探的深入,地质认识不断创新,在川东北地区万源—达州发现了一近北东向展布的克拉通内裂陷。利用地震、野外露头资料,结合盆地区域构造背景分析,勾绘了万源—达州内裂陷的边界与空间展布,梳理了裂陷演化及其理论与勘探意义。研究揭示:(1)震旦系灯一、二段在地震剖面上有明显的"陡坎"带,显示台地边缘相带的存在,总体呈近北东向展布;(2)裂陷周缘灯影组一、二段较厚,灯影组三、四段较薄,裂陷内部灯影组一、二段较薄,灯影组三、四段较厚;(3)裂陷演化分为震旦纪灯一段—灯二段沉积期的形成阶段、灯三段—灯四段沉积期的充填与沉降阶段以及早寒武世麦地坪组—筇竹寺组沉积期的萎缩—消亡3个阶段,其形成受早期南华纪裂谷及区域性隆升联合控制。万源—达州克拉通内裂陷的发现改变了四川盆地震旦纪—早寒武世构造沉积格局的传统认识,该裂陷周缘震旦系天然气成藏条件有利,是今后的重要勘探方向。
[Abstract]:With the further exploration of natural gas from Sinian to Cambrian in Sichuan Basin, geological knowledge has been innovated constantly, and a cratonic inner rift has been discovered in Wanyuan-Dazhou, northeast Sichuan. Using earthquake and outcrop data, Based on the analysis of the regional tectonic background of the basin, the boundary and space distribution of the Wanyuan-Dazhou rift is drawn, and the evolution of the rift and its theoretical and exploration significance are combed. There are obvious "steep ridges" in the seismic section of the second member, which shows the existence of the platform margin facies belt, which is generally near NE direction. The Dengying formation around the rifting margin is 1, the second stage is thicker, the third and fourth sections of the Dengying formation are thin, and the inner Dengying formation is one. The rift evolution of the thin Dengying formation and the third and fourth member of Dengying formation can be divided into the forming stage of the deposit period of the first and second member of the Landian formation in the Sinian. The filling and subsidence stages of the deposit period of the third and fourth member of the Lantern formation and the atrophy and extinction of the early Cambrian Madiping formation and Qiongzhusi formation. Its formation is controlled by the early South China rift and regional uplift. The discovery of Wanyuan-Dazhou craton rift has changed the traditional understanding of the Sinian to early Cambrian tectonic sedimentary pattern in Sichuan Basin. It is an important exploration direction in the future because of favorable reservoir forming conditions of Sinian gas in the margin of the rift.
【作者单位】：中国石油勘探开发研究院;
【基金】：国家科技重大专项(2016ZX05007)
【分类号】：P618.13

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