自然伽马能谱在塔中地区晚奥陶世碳酸盐岩层序地层分析中的应用

 文中以自然伽马能谱测井资料为基础，应用层序地层学的基本原理，对塔中地区晚奥陶世沉积层序、体系域及海平面升降的变化趋势进行了研究，结果表明：①晚奥陶世良里塔格组可以识别出1个二级层序，3个三级层序和5个四级层序，同时建立了研究区晚奥陶世海平面变化曲线；②层序O3l1和O3l2发育高位体系域和海侵体系域，没有低位体系域的沉积记录，而层序O3l3仅发育海侵体系域，称之为海侵层序；③沉积记录对海平面的响应关系表明，塔中凸起晚奥陶世碳酸盐岩台地的演化是一个淹没事件，有利储集相带礁滩复合体主要位于海侵体系域的底部和高位体系域的上部，而烃源岩在层序格架内具有明显的非均质性，主要分布在海侵体系域内；④钍和钾的移动平均曲线的高值与烃源岩有机碳总量的高值具有良好的对应关系，能快捷、完整地指示烃源岩在层序格架中的分布位置。

Application of natural gamma ray spectrometry in analysis of Late Ordovician carbonate sequence stratigraphic analysis in middle Tarim Basin

Late Ordovician Tarim area is an edging carbonate platform.Based on natural gamma spectral logging data and the principle of sequence stratigraphy,the sedimentary sequences in Late Ordovician,the system tract and the change trends for sea-level lifting and drop have been studied.A second-order sequence,3 third sequences and 5 fourth sequences were identified in Late Ordovician Shiliang Lianglitage formation,meantime the sea level change curve in Late Ordovician was generated.The highstand system track and t...