文档介绍：
地层记录中沉积旋回周期检测及沉积速率
变化曲线重建#
伊海生*
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(成都理工大学沉积地质研究院,成都 610059)
摘要:地层记录中普遍存在等级不同的沉积节律,其中又以砂岩和泥岩交替出现的米级沉积
旋回最为常见。旋回厚度是度量旋回在深度域变化尺度的一个最直观的定量参数,也是旋回
地层研究中提取周期信号的常用指标。
本文根据旋回厚度变化的地层模型,采用时频分析方法,解析了地层间断、沉积事件和
沉积速率变化对旋回周期信号的影响,建立了地层记录中旋回叠置型式的判别标志。文中提
出,深度域旋回周期长度的变化主要受到沉积物堆积速率的控制,根据旋回主导周期的在垂
向变化,可以绘制相对沉积速率变化曲线,而旋回谱系的突变面,指示沉积体制转型界面的
深度位置。
文中以柴达木盆地东部马海 10 井为例,介绍了应用自然伽马测井曲线计算砂泥岩旋回
厚度的方法和流程,采用滑移窗频谱分析了旋回周期变化的特点和谱系。研究结果表明,下
油砂山组、上干柴沟组和下干柴沟组地层单元的旋回周期长度一般为 10m 级大小,一般都
表现为多周期分布的频谱结构,而且旋回主导周期随着深度变化显示阶步式偏移的特点。下
油砂山组与下伏上干柴沟之间沉积速率的快速变化可能具有普遍意义,它反映青藏高原北部
造山带在渐新世-中新世之交存在一次构造隆升过程。
关键词:地质学;沉积旋回; 周期信号; 频谱分析; 沉积速率; 测井曲线
中图分类号:
Detection of sedimentary cycle periods in stratigraphic
record and sedimentation rate reconstruction
YI Haisheng
(Institute of Sedimentary Geology, Chengdu University of Technology,chengdu 610059)
Abstract: Sedimentary rhythm of different levels is often encountered in stratigraphic record, where
meter-scale sedimentary cycles with alternating of sandstone and shale are the mon types.
Cyclic thickness is a quantitative parameter to measure cycle variation scale in depth domain, and a
monly used index to extract period signals in cyclic stratigraphy study.
Based on the stratigraphic model of cyclic thickness variation, we studied the influence of stratigraphic
break, sedimentary event and sedimentation rate variation on cyclic period signals, and established the
diagnostic criterion for cycle superimposition forms in stratigraphic record using time-frequency
analysis. It was put forward in this paper that cyclic period variation in depth domain was mainly
controlled by sediment accumulation rate. Sedimentation rate curve can be reconstructed based on the
vertical change of main period of cycles. The shift surface of cycle spectral peaks can indicate
conversion depth of sedimentation regimes.
Taking Mahai 10 well in eastern Qaidam basin as case study, we introduced the method of using GR
log to cal