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  

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

作　　者：阳孝法[1,2] 林畅松[1] 杨海军[3] 彭莉[1,2] 刘景彦[1] 肖天君[3] 佟建宇[1] 王海平[1] 李换浦[1] 

机构地区：[1]中国地质大学能源学院,北京100083 [2]海相储层演化与油气富集机理教育部重点实验室,中国地质大学,北京100083 [3]中国石油天然气股份有限公司塔里木油田分公司,新疆库尔勒841000

出　　处：《石油地球物理勘探》2010年第3期384-391,共8页Oil Geophysical Prospecting

基　　金：国家重点基础研究发展计划(973)项目“中国西部典型叠合盆地隆坳格局形成演化与岩性地层圈闭发育模式”(编号:2006CB202302)资助

摘　　要：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。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 the transgressive system tract were developed in the O3l1 sequence and the O3l2 sequence,no record shows lowstand system tract,the transgressive system tract was only developed in O3l3,called transgressive sequence.The sediment record’s response relation indicates that the evolution of the Late Ordovician platform in Central Tarim Basin Uplift was a flooding event.The reef-bank complex which is the favorable reservoir facies is mainly located in the lower part of the transgressive system tract and in the upper part of the highstand system track,while the source rocks in the sequence framework shows a significant heterogeneity,mainly distributing in transgressive system tract.The high values of the Thorium and potassium in the moving average curve and high-values of the source rock's total organic carbon amount show a good corresponding relationship,so the distribution location of the source rock in sequence framework can be quickly and completely identified.

关 键 词：塔里木盆地 晚奥陶世 碳酸盐岩台地 沉积层序 海平面变化 自然伽马能谱 

分 类 号：P618.110.2[天文地球—矿床学]