论文部分内容阅读
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O3l1和O3l2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O3l3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。
Based on the log data of natural gamma ray spectrometry and the basic principles of sequence stratigraphy, the authors studied the changes of sedimentary sequence, system tract and sea level rise and fall of the Late Ordovician in the Tarim Basin. The results show that: ① Late Ordovician Lianglitage Formation can identify one second-order sequence, three third-order sequences and five fourth-order sequences, meanwhile establish the sea level change curve of Late Ordovician in the study area. ② Sequence O3l1 and There is no sedimentary record of lowstand system tract in O3l2 developmental system tract and transgressive system tract, while sequence O3l3 only develops transgressive system tract, which is called transgressive sequence. (3) The response relationship of sedimentary record to sea level shows that the tower The evolution of the mid-convex late Ordovician carbonate platform is a submerged event. The reef-facies complex of the favorable reservoir facies is mainly located at the bottom of the transgressive system tract and the upper part of the highstand system tract. There are obvious heterogeneities in the grid and are mainly distributed in the transgressive system tract. (4) The high value of the moving average curve of thorium and potassium has a good correspondence with the high value of total organic carbon in source rocks, Completely indicate the location of source rocks in the sequence framework