论文详情
海上地震勘探中, 鬼波对地震信号的陷波是海洋宽频地震勘探面临的主要挑战之一。进行合理的双检合并, 分离上、下行波场一直是深水OBN地震数据成像处理关注的焦点之一。双检合并过程中, 通过建立上、下行波场和水、陆检波场之间的数学关系, 解决好水、陆检信号匹配是关键。深水OBN地震数据中, 静校正难题和陆检中的横波泄漏噪声等因素导致基于反射波的双检匹配效果不好。提出了选取小时窗的直达波进行线性动校正和共检波点叠加, 利用水、陆检数据共检波点叠加后的直达波信号求取每一个检波点的双检匹配算子的方法, 用求取的匹配算子进行双检匹配, 进而分离上、下行波场。用直达波求取双检匹配算子不需要交叉鬼波化, 使用简便, 可以避开反射波求取双检匹配算子时噪声等因素的影响。该方法在深水地震数据处理中的应用表明, 用直达波求取的深水OBN双检匹配算子更加稳定, 用求取的匹配算子校正后进行双检合并可以实现良好的深水OBN地震数据波场分离。
In deep-water exploration, the frequency notch of seismic signals caused by ghost at the receiver point poses a major challenge to broadband seismic exploration. The point is how to separate upgoing and downgoing wave fields for dual-sensor combination, which relies on the mathematical relations between upgoing and downgoing wave fields and between geophone and hydrophone wave fields for dual-sensor calibration. The challenge is that inaccurate static correction and S-wave noises in geophone records will deteriorate dual-sensor calibration based on reflected waves. Our method uses direct waves within a small time window for LMO correction and common receiver stacking, and then the operator at each receiver point is derived from stacked direct waves of geophones and hydrophones for dual-sensor calibration, followed by the separation of upgoing and downgoing wave fields. Cross-ghosting is unnecessary in this process, and operator calculation will not be affected by noises owing to the utilization of direct waves instead of reflected waves. As shown by deep-water seismic data processing, the operators obtained from direct waves for deep-water OBN dual-sensor calibration are more robust and perform well in OBN wave field separation after dual-sensor calibration and combination.