开江-梁平陆棚东南延伸部分——建南陆棚的发现

自王一刚发现开江-梁平陆棚后,作者对其东南延伸部位进行了追踪。通过地表露头剖面及钻井、地震资料等研究后认为,长兴期开江-梁平陆棚自宣汉达县、梁平及开江地区向东南延伸至建南地区,称之为建南陆棚,该陆棚可能与东部的鄂西陆棚相连。建南陆棚与开江-梁平陆棚既有相似性也有重大差别。相似性表现在两方面,一是沉积物岩性相似,都为泥晶灰岩;二是陆棚边缘都发育生物礁,生物礁顶部发育生屑滩白云岩储层。差别主要体现在四个方面:一是水体深度,建南陆棚水浅,开江-梁平陆棚水深,深水与浅水的交汇处在涪陵地区中石化二维地震剖面线TB16与TB17之间;二是斜坡坡度,开江-梁平陆棚边缘斜坡坡度陡,建南陆棚斜坡坡度缓;三是生物礁规模,开江-梁平陆棚边缘生物礁、白云岩储层厚度大,建南陆棚边缘生物礁、白云岩储层厚度小;四是陆棚发育时间,建南陆棚仅发育于长兴早中期,晚期因填平补齐而消失,开江-梁平陆棚发育于整个长兴期。建南陆棚与周边构成碳酸盐缓坡沉积模式,生物礁规模较小,生物礁是优质储发育的主要地区。

The discovery of the Jiannan shelf in the southeastern part of the KaijiangLiangping shelf

On the basis of outcrops,cores and seismic data in this study and the previous data,the author in this study proposes a new shelf,i.e.,the Jiannan shelf that represents the southeastward extended part of the KaijiangLiangping shelf penetrated from the Xuanhan-Daxian-Liangping-Kaijiang zone southeastwards to the Jiannan area during the Changxingian,and may be connected with West Hubei shelf in the east.Compared with the KaijiangLiangping shelf,the Jiannan shelf has the following features.（1） The Jiannan shelf is a shallow-water shelf.（2）The Jiannan shelf was initiated during the early-middle Changxingian and terminated due to the filling up during the late stages of the Changxingian.（3） The Jiannan shelf and its adjacent areas exhibit a carbonate ramp model in which the Changxingian bioherms occur as excellent dolostone reservoirs with good physical properties.