论文详情
随着“两宽一高”地震数据采集技术及地震波成像技术的进步, 薄层、小尺度（缝洞）异常体、小断距断层（走滑断层）等成为了高保真高分辨地震波成像的主要目标地质体。当前地震勘探中, 合理的观测系统设计得到了充分的关注, 但如何实现客户定制高分辨率子波却很少被讨论。可控震源理论上是在频率时间域通过单频时间能量累计得到期望地震子波振幅谱的一种震源。基于此, 提出了客户定制高分辨率地震子波及对应的扫描信号的概念, 基本流程为：首先在特定目标层上生成（或客户定制）一个满足保真分辨率要求的零相位子波, 同时得到其对应的振幅谱; 然后建立定制子波振幅谱和可控震源扫描信号之间的映射关系; 最后在扫描频率线性变化情况下, 设计出可控震源扫描信号。公式推导和数据测试均证明了基于定制高分辨率子波来设计可控震源扫描信号的可行性。正演模拟和偏移试验结果表明, 利用定制的高分辨率子波可以有效保持后续处理资料的高分辨率特征。
Due to the advancements of seismic data acquisition and imaging with "wide band, wide azimuth, and high density", thin layers, small-scale (fractured-vuggy) anomalous bodies, and small-throw faults (strike-slip faults), etc. have become the main target geological bodies for high-fidelity and high-resolution imaging. In current seismic exploration, reasonable observation system design has received sufficient attention, but how to achieve customized high-resolution wavelets for the customers is rarely discussed. In theory, vibroseis is a method of obtaining the amplitude spectrum of expected seismic wavelet through the accumulation of single-frequency energy within time intervals in the frequency and time domain. Based on this, we propose the concept of customized high-resolution seismic wavelets and corresponding sweep signals for the customers. The first step is to generate (or customize) a zero-phase wavelet, which meets the requirements of high-fidelity and high-resolution on a specific target layer, and obtain its corresponding amplitude spectrum. The second step is to establish the mapping relationship between the amplitude spectrum of the customized wavelet and the vibrator sweep signals. Finally, the vibrator sweep signals are designed under the assumption of linear sweep frequency. We use formula derivation and model tests to demonstrate the feasibility of our method. Forward modeling and migration tests also show that the customized high-resolution wavelet could be used in high-resolution processing.