频谱分析法确定乌什凹陷白垩系米氏沉积旋回及沉积速率  

Applying Frequency Spectral Analysis to Identify Milankovitch Cycle and Calculate Sedimentation Rate of Cretaceous in Wushi Sag

作　　者：郑民[1] 彭更新[2] 雷刚林[2] 黄少英[2] 吴超[2] 郭华清[2] 李曰俊[3] 

机构地区：[1]中国科学院地质与地球物理研究所兰州油气资源中心 [2]中国石油塔里木油田分公司,新疆库尔勒841000 [3]中国科学院地质与地球物理研究所,北京100029

出　　处：《新疆石油地质》2007年第2期170-174,共5页Xinjiang Petroleum Geology

基　　金：国家973项目;高效天然气藏形成分布与凝析;低效气藏经济开发的基础研究(2001CB209104-04);国家自然科学基金项目;塔里木盆地北缘始新统-古新统磁性地层划分(400704014)共同资助

摘　　要：以自然伽马曲线包含的丰富地质信息为基础,通过小波分析与快速傅里叶变换相结合,运用频谱分析法在乌什凹陷白垩系识别出米兰柯维奇沉积旋回,并确定出米氏旋回的厚度,在此基础上精确计算出资料区白垩系各层组沉积速率。其中偏心率周期引起的地层旋回厚度变化为8.70～13.89m;地轴倾角周期引起的地层旋回厚度变化为3.01～5.88m;岁差周期引起的地层旋回厚度变化为1.28～2.44m.4口采样井白垩系地层平均沉积速率为0.09378mm/a.Based on abundant information of gamma-ray curves, combining wavelet analysis with fast Fourier transform, the Milankovitch cycle and its thickness of Cretaceous in Wushi sag is identified using frequency spectral analysis, then the sedimentation rates of each layer of Cretaceous in studied area are precisely calculated. The results show that the thickness of sedimentary cycle caused by eccentricity cycle ranges from 8.70 m to 13.89 m; the thickness of it caused by obliquity cycle from 3.01 m to 5.88 m; the one of it by precession cycle from 1.28 m to 2.44 m, and the average sedimentation rate of Cretaceous strata from four sampling wells is 0.093 78 mm/a.

关 键 词：乌什凹陷 自然伽马曲线 傅里叶变换 沉积旋回 沉积速率 

分 类 号：TE111.3[石油与天然气工程—油气勘探]