可控震源非线性扫描在高分辨率地震采集中的应用

Application of vibroseis nonlinear sweep in high resolution seismic data acquisition in S area, Kazakstan

(中国石油化工股份有限公司华东分公司资料处理解释中心，江苏南京210007)

Data Processing and Interpretation Center of East China Branch Company, SINOPEC, Nanjing 210007, China

可控震源的扫描信号可以控制，对环境破坏较小，特别适合炸药震源禁区的地震数据采集。扫描信号的理论基础是线性信号，但是地下介质对地震波的吸收衰减是非线性的，因此线性扫描不能对高频衰减进行补偿，降低了信号的信噪比，由此发展了非线性扫描技术。非线性扫描技术的扫描速率不再是常数，通过在高频段合理增加扫描时间来实现对高频衰减的补偿，达到提高地震分辨率的目的。在哈萨克斯坦S区的高分辨率地震数据采集中，采用非线性扫描技术，通过对扫描参数的优选，对高频能量进行了有效补偿，取得了较好的效果，实现了高分辨率地震数据采集。

Vibroseis is especially suitable to the seismic data acquisition at explosive forbidden zone for its controllable shooting waveform and less damage to environment. The theory of sweep signal is based on linear signal. However, the absorption attenuation of seismic energy caused by subsurface media is nonlinear. Therefore, linear sweep is unable to compensate for the high frequency attenuation and reduces the S/N ratio. Aiming at this problem, we developed the nonlinear sweep technology whose scanning velocity was no longer a constant. In using this method, the compensation for high frequency attenuation can be achieved by reasonably prolonging the sweep time to improve the seismic resolution. In the application of the nonlinear sweep technology in data acquisition in S area of Kazakhstan, by optimizing sweep parameters and effectively compensating the energy of high frequency, we have achieved good result and realized data acquisition with high resolution.