基于波动方程的共聚焦点成像技术

Common focuspoint imaging based on wave equation

(1.中国石油大学地球资源与信息学院,山东东营257061;2.中国石油勘探开发研究院西北分院，甘肃兰州730020)

College of Geo-resources and Information, China University of Petroleum, Dongying 257061, China

对于较复杂的理论模型和低信噪比的实际地震资料处理来说，用基于射线理论的有限差分走时法共聚焦点(CFP)成像技术生成的CFP偏移剖面不能精确地对地下构造成像。为此，探讨了基于波动方程的傅里叶有限差分法(FFD)共聚焦点(CFP)成像技术。该技术可以自动检测宏观速度场正确与否，大大提高了聚焦算子的计算精度和双聚型保幅成像精度。数值模拟验证了方法的正确性，实际资料处理验证了方法的有效性和实用性。与基于射线理论的有限差分走时法的CFP成像剖面对比结果表明，基于波动方程的CFP偏移剖面分辨率更高，层位更清楚，可以对地下构造清晰成像。

The common focus-point(CFP) imaging technology utilizes ray-theory-based finite difference travel-time method. In complex theoretical model and actual low S/N seismic data processing, the generated CFP imaging profiles can not exactly image the subsurface structures. Therefore, the CFP using the wave-equation-based Fourier finite difference method is discussed. This technology can automatically detect the correctness of velocity field, which greatly improves the computation accuracy of focusing operator and the accuracy of bifocal amplitude-preserving imaging. Numerical simulation has verified the correctness of the method and actual data processing has proved its validity and practicability. Compared to the ray-theory-based CFP imaging profiles, the wave-equation-based CFP profiles have higher resolution and clearer stratigraphic horizons, which can clearly image the subsurface structures.