{"title":"Spectral decomposition predicts the distribution of steep slope fans in the rift basin of eastern China","authors":"","doi":"10.1016/j.jappgeo.2024.105543","DOIUrl":null,"url":null,"abstract":"<div><div>Deep reservoirs associated with gravity-flows are garnering considerable attention. Predicting reservoirs deposited by nearshore subaqueous fans is challenging and often underreported in seismic sedimentology analysis. Utilizing post-stack seismic attributes is a quick and straightforward method for quantitatively characterizing these reservoirs. However, reservoir prediction deteriorates when dealing with complex sedimentary volumes and intricate tectonic development. Spectral decomposition (SD) offers an alternative approach to optimize the seismic data. The frequency-dependent S-transform (ST) holds great potential in seismic interpretation. SD based on the ST was employed in the seismic sedimentary characterization of steep slope complex fan reservoirs. Three fourth-order sequence stratigraphic boundaries and three complex fans were ideally shown on seismic frequency decomposition profiles. A 20 Hz seismic sedimentology analysis frequency was determined by comparing three spectral decomposition results following the well-seismic reflection analysis. The internal architectures of fan deltas and the individual outlines of nearshore subaqueous fans were more distinguishable in 20-Hz frequency decomposition data than in full-frequency data. The progradation direction of steep slope fans can be better recognized in frequency decomposition profiles compared to full-frequency seismic data. Three factors influence the seismic sedimentary characterization and prediction of steep slope fans when employing SD. The ability of the ST to preserve phase is crucial for improving the imaging quality of the amplitude attribute. Sedimentary mechanisms control the sedimentary features of steep slope fans, impacting the imaging of seismic attributes. While channelized fan deltas can be better identified, unchannelized nearshore subaqueous fan deposits, which exhibit more heterogeneous sedimentary characteristics, present limitations. The unique volcanic evolution is another factor that impacts the image of the root-mean-square (RMS) attribute. Despite demonstrating excellent local adaptability in signal analysis, the S-transform cannot fully compensate for the combined effects of faults and sedimentary heterogeneity in nearshore subaqueous fans.</div></div>","PeriodicalId":54882,"journal":{"name":"Journal of Applied Geophysics","volume":null,"pages":null},"PeriodicalIF":2.2000,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Applied Geophysics","FirstCategoryId":"89","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0926985124002593","RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"GEOSCIENCES, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
Deep reservoirs associated with gravity-flows are garnering considerable attention. Predicting reservoirs deposited by nearshore subaqueous fans is challenging and often underreported in seismic sedimentology analysis. Utilizing post-stack seismic attributes is a quick and straightforward method for quantitatively characterizing these reservoirs. However, reservoir prediction deteriorates when dealing with complex sedimentary volumes and intricate tectonic development. Spectral decomposition (SD) offers an alternative approach to optimize the seismic data. The frequency-dependent S-transform (ST) holds great potential in seismic interpretation. SD based on the ST was employed in the seismic sedimentary characterization of steep slope complex fan reservoirs. Three fourth-order sequence stratigraphic boundaries and three complex fans were ideally shown on seismic frequency decomposition profiles. A 20 Hz seismic sedimentology analysis frequency was determined by comparing three spectral decomposition results following the well-seismic reflection analysis. The internal architectures of fan deltas and the individual outlines of nearshore subaqueous fans were more distinguishable in 20-Hz frequency decomposition data than in full-frequency data. The progradation direction of steep slope fans can be better recognized in frequency decomposition profiles compared to full-frequency seismic data. Three factors influence the seismic sedimentary characterization and prediction of steep slope fans when employing SD. The ability of the ST to preserve phase is crucial for improving the imaging quality of the amplitude attribute. Sedimentary mechanisms control the sedimentary features of steep slope fans, impacting the imaging of seismic attributes. While channelized fan deltas can be better identified, unchannelized nearshore subaqueous fan deposits, which exhibit more heterogeneous sedimentary characteristics, present limitations. The unique volcanic evolution is another factor that impacts the image of the root-mean-square (RMS) attribute. Despite demonstrating excellent local adaptability in signal analysis, the S-transform cannot fully compensate for the combined effects of faults and sedimentary heterogeneity in nearshore subaqueous fans.
与重力流相关的深层储层正受到广泛关注。预测近岸水下扇沉积的储层具有挑战性,在地震沉积学分析中往往报告不足。利用叠后地震属性是定量描述这些储层特征的快速而直接的方法。然而,在处理复杂的沉积体积和错综复杂的构造发展时,储层预测会恶化。频谱分解(SD)为优化地震数据提供了另一种方法。频率相关的 S 变换(ST)在地震解释中具有巨大潜力。在对陡坡复杂扇形储层进行地震沉积特征描述时,采用了基于 ST 的频谱分解。在地震频率分解剖面上理想地显示了三个四阶层序地层边界和三个复合扇。通过比较井震反射分析后的三个频谱分解结果,确定了 20 赫兹的地震沉积分析频率。与全频数据相比,20 赫兹频率分解数据更能区分扇三角洲的内部结构和近岸水下扇的个体轮廓。与全频地震数据相比,频率分解剖面能更好地识别陡坡扇的渐变方向。使用频率分解数据时,有三个因素会影响陡坡扇的地震沉积特征描述和预测。ST 保留相位的能力对于提高振幅属性的成像质量至关重要。沉积机制控制着陡坡扇的沉积特征,影响着地震属性的成像。渠道化的扇形三角洲可以更好地识别,而非渠道化的近岸水下扇形沉积则表现出更多的异质沉积特征,因此存在局限性。独特的火山演化是影响均方根(RMS)属性图像的另一个因素。尽管 S 变换在信号分析中表现出出色的局部适应性,但它无法完全补偿近岸水下扇形沉积中断层和沉积异质性的综合影响。
期刊介绍:
The Journal of Applied Geophysics with its key objective of responding to pertinent and timely needs, places particular emphasis on methodological developments and innovative applications of geophysical techniques for addressing environmental, engineering, and hydrological problems. Related topical research in exploration geophysics and in soil and rock physics is also covered by the Journal of Applied Geophysics.