湘中地区下寒武统烃源岩沉积环境及其特征

本文通过对湘中地区早寒武世岩相古地理的研究,认为早寒武世期间,湘中地区为发育在陆架之上的缺氧滞留盆地沉积环境,沉积了一套以黑色炭质板状页岩及含硅质炭质泥岩等为主的黑色沉积。该套黑色沉积沿着湘中地区以及扬子东南缘呈带状稳定分布,反映出当时湘中地区是一＂富烃沉积区＂,具有生烃潜力;该套寒武纪海相地层是油气勘探的重要层位。

Sedimentary environments of the Lower Cambrian source rocks in central Hunan

Tectonically,central Hunan lies on the southeastern margin of the middle-upper Yangtze plate.During the Early Cambrian,this region was in a relatively stable cratonic basin.The integration of upwelling oceanic currents,sea-level rises and anoxic events gave rise to the formation of the favourable environments for the generation of source rocks.Throughout the Early Cambrian,the central Hunan region was once developed as the anoxic stagnant basin above the continental shelf,and composed of a succession of black deposits comprising black carbonaceous tabular shales and siliceous-carbonaceous mudstones.The black deposits extend from the central Hunan region to the whole southeastern margin of the middle-upper Yangtze plate,implying that the study area was then enriched in hydrocarbons,and thus has great hydrocarbon potential.This region is selected as a key area not only for basic geological survey and oil and gas exploration,but also for the exploration of shale gas.