有限差分法波场延拓海水层基准面校正

在海上多波地震勘探中,野外施工设计采用海水中激发,海底接收的观测方式.由于炮点和检波点不在一个基准面上,就带来了基准面校正问题.在选定海底为基准面后,通常将炮点校正到海底,若海水层的深度超过100m,简单时移校正的误差比较大,应该采用更精确的波场延拓基准面校正方式.对理论合成记录和莺歌海地区的实际资料进行了方法测试,效果令人满意.

WATER LAYER DATUMING WITH FINITE-DIFFERENCE WAVEFIELD EXTRAPOLATION SCHEME

In recent offshore multiwave survey,the sources are positioned on sea surface while the receiver cable is located on the sea floor for the convenience of survey. Seismic data acquired by this geometry need to be datum corrected because sources and receivers are located on a non-flat surface. Usually we adopt elevation statics to do this job,but for big differences in elevations between sea surface and sea floor,the accuracy ofthe statics may prove to be insufficient;a more exact method-wave equation datuming should be usedinstead. Application of the wavefield extrapolation to synthetic data demonstrates it provides accurate datum corrections,the algorithms have also been applied to real data.