哈萨克斯坦滨里海盆地盐下成像技术应用研究

哈萨克斯坦滨里海盆地盐下地震勘探存在盐丘屏蔽、干扰波发育、反射波能量弱、先验资料缺乏以及因速度异常引起的构造假象等问题.通过合理组织处理流程,有效压制了面波干扰、规则干扰、强能量干扰和随机噪声干扰;采用由粗到细的思路,先利用谱分析方法建立宏观速度场,再利用射线层析成像方法提高速度分析精度,建立了较为准确的速度模型;利用频率-空间域有限差分叠前深度偏移解决了盐下及盐丘侧翼的成像问题.上述特色处理技术的应用,使得哈萨克斯坦滨里海盆地盐下及盐丘侧翼反射清楚,有效消除了由速度异常造成的构造假象.

Subsalt imaging technique used in Caspian seashore basin, Kazakhstan

There exist some problems in subsalt seismic exploration of Caspian seashore basin, such as salt doom screening, interference wave development, weak energy of reflected wave, shortage of prior data and pseudo-structures caused by velocity anomaly, etc. Aiming at these problems, we have designed the processing workflow to effectively suppress the surface wave interference, regular interference, high energy interference, and other random noise interference. The treatment clue was from thick to thin. Firstly, the spectral analysis method was used to establish macroscopic velocity field. Then, the ray tomography method was used to enhance the accuracy of velocity analysis and to establish a more accurate velocity model. Finally, the finite difference pre-stack depth migration method in f-k domain was adopted to solve the imaging problem of subsalt and salt dome flank. The data processing result demonstrates that using the above treatment scheme can clearly image the subsalt and salt dome flank and effectively remove the structure artifacts caused by the velocity anomaly.