中扬子地区下寒武统烃源岩横向分布及主控因素分析

基于前人研究资料和野外露头剖面详细观测及样品实测数据,讨论了中扬子地区下寒武统烃源岩的横向分布特征,探讨了烃源岩横向分布的主控因素.研究认为:中扬子地区下寒武统烃源岩围绕中扬子碳酸盐台地呈环状分布;台地内没有烃源岩发育,向洋一侧烃源岩逐渐加厚.研究区下寒武统烃源岩的分布受控于早寒武世早期盆地原型的分布,烃源岩的发育受沉积相控制.烃源岩所发育的相带均为陆棚边缘盆地相,早寒武世沧浪浦期—龙王庙期的浅海陆棚相、滨浅海相、台缘滩相、台缘斜坡相、局限台地相等沉积相带的碎屑岩、碳酸盐岩有机质含量均较低,烃源岩发育极差.

Transverse distribution of Lower Cambrian hydrocarbon source rocks in the middle Yangtze region and its major control factors

The lateral distribution of Lower Cambrian source rocks in middle Yangtze region and its main control factors are systematically discussed based on the results of previous research,the observation of field outcrop and the measuring data of natural rock samples.It is held that Lower Cambrian source rock shows the ring distribution around the carbonate platform in middle Yangtze region and there is no development of hydrocarbon source rocks in the platform.The hydrocarbon source rocks become gradually thick toward the ocean side.The lateral distribution of Lower Cambrian source rocks is controlled by the distribution of the early prototype basin of early Cambrian,and the development and distribution of hydrocarbon source rocks are controlled by sedimentary facies.All the hydrocarbon source rocks distribute in the shelf border basin facies.Their development is poor in the sedimentary facies belt of neritic shelf facies,littoral neritic facies,platform margin beach facies,platform margin slope facies,restricted platform facies in Canglangpu and Longwangmiao Ages of Early Cambrian,because the organic matter content of the clastic rocks and carbonate rocks in them is very low.