基于连续小波变换的黑北凹地砂砾储卤层沉积特征研究  

Research of sedimentary characteristics on gravel brine reservoir in Heibei concave based on continuous wavelet transform

作　　者：侯献华[1] 王伟[2] 郑绵平[1] 皮晨 樊馥[1] 苏奎[1] 李洪普 高雪峰 HOU Xianhua;WANG Wei;ZHENG Mianping;PI Chen;FAN Fu;SU Kui;LI Hongpu;GAO Xuefeng(MNR Key Laboratory of Saline Lake Resources and Environments,Institute of Mineral Resources,CAGS,Beijing 100037,China;Institute of Geographic Sciences and Natural Resources Research,Chinese Academy of Science,Beijing 100101,China;Qinghai Qaidam Integrated Institute of Geology and Mineral Resource Exploration,Golmud,Qinghai 816000,China;Qinghai Oilfield Company,PethoChina,Dunhuang,Gansu 736202,China)

机构地区：[1]中国地质科学院矿产资源研究所,自然资源部盐湖资源与环境重点实验室,北京100037 [2]中国科学院地理科学与资源研究所,资源与环境信息系统国家重点实验室,北京100101 [3]青海省柴达木盆地盐湖资源勘探研究重点实验室,青海省柴达木综合地质矿产勘查院,青海格尔木816000 [4]中国石油青海油田分公司,甘肃敦煌736202

出　　处：《地质学报》2024年第10期2956-2967,共12页Acta Geologica Sinica

基　　金：国家重点研发计划课题“青海柴北陆相深层砂砾型卤水富钾规律、勘查技术与增储示范”(编号2023YFC2906501);自然资源部高原荒漠区战略性矿产勘查开发技术创新中心开放研究课题(编号KFKT20230103);中国地质调查项目(编号DD20230755)联合资助的成果。

摘　　要：柴达木盆地西部中深层“砂砾型”钾盐储卤层与沉积水体变化息息相关,高密度网状二维地震资料包含的频率信息,有助于识别发育砂砾储卤层的沉积环境,为深层富钾卤水储层研究提供支撑。采用连续小波变换时频分析技术将地震信号从一维的时间域拓展到二维的时间-频率域上,能够在频谱中更清晰地刻画沉积体内部岩性组合的旋回结构特征。基于正演数据和实际钻井数据,总结了低水位体系域、水进体系域、高水位体系域和水退体系域层序框架下,沉积体的地震时频谱旋回响应特征:低水位体系域的时频谱能量主要聚集在低频,高水体系域的时频谱能量主要聚集在高频,水进体系域的时频谱能量随时间减小向高频方向移动,水退体系域的时频谱能量随时间减小向低频方向移动,指出35 Hz是划分有利沉积旋回——水退体系域末期、低水位体系域和水进体系域初期的频率阈值。选择合适频率区间重构地震数据能突出弱振幅砂砾层的反射特征,结合全频带数据有助于快速识别有利沉积旋回,为寻找砂砾型深层卤水钾矿提供依据。The middle and deep potassium salt reservoirs in the western Qaidam basin are closely related to sedimentary water changes.High-density two-dimensional seismic data,with its rich frequency information,helps in identifying sedimentary environments and provides support for the study of deep potassium-rich brine reservoirs.Continuous wavelet transform time-frequency analysis extends seismic signals from the one-dimensional time domain to the two-dimensional time-frequency domain.This allows for a can more clearlyer characterization of the cyclic structural characteristics inside within sedimentary bodies and their lithological associations in the frequency spectrum.Based on forward modeling data and actual drilling data,the corresponding seismic time-frequency signature of sedimentary bodies were concluded under the sequence stratigraphy framework(low-stand system tract(LST),transgressive system tract(TST),high-stand system tract(HST)and regressive system tract(RST)).The timefrequency energy of LST is mainly concentrated at low frequencies,while high-frequencies for HST.The time-frequency energy of TSTdecreases over time and shifts toward a higher frequency and conversely,for RST we identified 35 Hz as a key frequency threshold for dividing favorable sedimentary cycles,marking the transition between the end of RST,and the early stage of LST or HST.Selecting an appropriate frequency range for seismic data reconstruction can enhance the reflection characteristics of low-amplitude sandstone.Combining this with full-frequency band data facilitates the rapid identification of favorable sedimentary cycles,providing a valuable basis for exploring gravel-type deep brine potassium deposits.

关 键 词：砂砾储卤层 连续小波变换 时频谱特征 沉积旋回 黑北凹地 

分 类 号：P619.211[天文地球—矿床学]