延庆盆地活断层探测超浅层反射地震数据高分辨率处理技术研究

发布时间：2018-02-09 09:22

本文关键词： 活断层超浅层地震高分辨率有效覆盖次数　出处：《中国地质大学(北京)》2017年硕士论文　论文类型：学位论文

【摘要】：延庆盆地是北京市西北约60km处的一个小型的新生代断陷山间盆地。自第三纪以来研究区强烈下沉,形成了巨厚的第四系沉积,盆地新构造差异活动强烈,发育多组活断层。活断层与地震和地质灾害紧密相关,活断层的超浅层精确定位对节约土地资源和首都圈的抗震减灾都具有重要意义。浅层地震勘探能有效解决城市近地表活动隐伏的活断层,能准确确定切割地层层位的位置。受到巨厚第四系覆盖,数据采集和处理的因素影响,超浅层地震数据处理存在以下问题:(1)受到炮源强噪音和随机噪音影响,超浅层地震数据近偏移距有效道数较少;(2)各向异性问题使基于双曲时距曲线的动校公式不适用,损失了远偏移距数据,导致超浅层有效覆盖次数低的问题;(3)由于研究区超浅层有效波出现在65Hz以上的高频端,主频在100-150Hz,中深层有效波在100Hz以上不具备足够高的信噪比,依靠深层有效波进行的剩余静校正无法准确求取超浅层有效波高频静校正量的问题;(4)超浅层的CMP道集有效道较少,会引起速度分析的不准确。本课题针对上述问题,主要研究以下内容:(1)应用LFAF去噪、叠前RNA随机噪音压制等方法实现超浅层地震数据的信噪分离,提高超浅层近偏移距的有效地震道数;(2)基于VTI介质的非双曲时距曲线动校方法对远偏移距数据进行有效校平,提高超浅层地震数据的有效覆盖次数;(3)应用高精度相干叠加方法,解决超浅层高频静校正量求取难的问题;(4)联合多个CMP道集组成超级道集做速度分析,提高超浅层速度分析的精度。本课题应用地震数据处理中的各向异性速度分析、高精度相干叠加、超级道集速度分析等方法处理超浅层地震数据,主要解决了以下几点:(1)通过针对性的超浅层信噪分离和基于VTI介质的非双曲时距曲线动校方法将0-50ms的有效覆盖次数从2-4次提高到了 5-10次;(2)应用超级道集的速度分析改善了速度谱的质量,提高了速度分析的精度;(3)应用相干高精度叠加方法,解决了高频静校正量求取难的问题,使叠前CMP道集中的高频有效波同相轴更平直,能够同相叠加。除此之外,在保证超浅层地震数据高信噪比的同时,使用了反Q滤波配合脉冲反褶积、谱均衡、谱模拟反褶积等技术大幅度提升了其分辨率,最终获得了 50ms以浅的高信噪比高分辨率地震剖面,为活断层超浅层精确定位解释提供了依据。
[Abstract]:Yanqing Basin is a small Cenozoic faulted intermountain basin located about 60 km northwest of Beijing. The study area has sunk strongly since the Tertiary, forming a very thick Quaternary sedimentary system, and the neotectonic differential activity of the basin is strong. Multiple active faults are developed. Active faults are closely related to earthquakes and geological hazards. The accurate location of ultra-shallow layers of active faults is of great significance for saving land resources and earthquake disaster reduction in the capital circle. Shallow seismic exploration can effectively solve the active faults with hidden activities near the surface of the earth. It can accurately determine the position of the cutting strata. It is affected by the factors of extremely thick Quaternary system covering, data acquisition and processing, and the following problems exist in the ultra-shallow seismic data processing: 1) affected by the strong noise and random noise of the gun source. The anisotropy problem makes the dynamic correction formula based on hyperbolic time-distance curve inapplicable, and the far-offset data is lost. The problem of low effective coverage of the ultra-shallow layer is caused by the fact that the ultra-shallow effective wave in the study area appears at the high frequency end above 65Hz, the main frequency is 100-150 Hz, and the mid-deep effective wave does not have a high signal-to-noise ratio (SNR) above 100Hz. Residual static Correction based on Deep effective Wave can not accurately calculate the High Frequency static Correction quantity of Ultra-shallow effective Wave. (4) there are fewer effective tracks of CMP gather in ultra-shallow layer, which will lead to inaccuracy of velocity analysis. This paper mainly studies the following contents: (1) LFAF denoising and prestack RNA random noise suppression are used to realize the separation of signal and noise from ultra-shallow seismic data. The effective seismic trace number of increasing the near migration distance of the ultra-shallow layer is improved.) based on the non-hyperbolic time-distance curve dynamic calibration method of VTI medium, the remote offset data are effectively calibrated, and the effective coverage times of the seismic data in the ultra-shallow layer are increased by using the high-precision coherent stacking method. In order to improve the accuracy of velocity analysis in ultra-shallow layer, we use the anisotropic velocity analysis in seismic data processing. High precision coherent stacking, super gather velocity analysis and other methods to deal with ultra-shallow seismic data, This paper mainly solves the following points: 1) the effective coverage of 0-50ms is improved from 2-4 times to 5-10 times by means of targeted ultra-shallow signal-noise separation and non-hyperbolic time-distance curve dynamic calibration method based on VTI medium) the speed of supergathers is applied. The analysis improves the quality of the velocity spectrum, The accuracy of velocity analysis is improved by using coherent high precision stacking method, which solves the problem of high frequency static correction, and makes the high frequency effective wave of prestack CMP trace concentration more straight and can be stacked in the same phase. In order to ensure high signal-to-noise ratio (SNR) of ultra-shallow seismic data, deconvolution, spectral equalization, spectral simulation deconvolution and other techniques such as anti-Q filter and pulse deconvolution are used to greatly improve the resolution of the seismic data. Finally, 50 Ms seismic profiles with shallow high signal-to-noise ratio and high resolution are obtained, which provides the basis for accurate location and interpretation of ultra-shallow layers of active faults.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P631.4

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