水陆检数据上下行波场分离方法

A separation method of up-going and down-going wavefields for dual-sensor seismic data

上下行波场分离是水陆检数据处理技术的关键步骤。针对常规方法分离出来的上行波场中包含下行波场、下行波场中包含上行波场,即不能实现上行波场与下行波场完全分离的缺陷,文中引入(水陆检数据、上行波场中下行波场及下行波场中上行波场等)三个能量匹配因子和(水检数据上行波场及下行波场、陆检数据上行波场及下行波场等)四个波场分离贡献因子,并建立上、下行波场分离方程;采用迭代方法计算确定最佳水陆检数据上、下行波场能量匹配因子;然后直接计算波场分离贡献因子,实现水陆检数据上下行波场完全分离处理。分离后的上行波场数据,既消除了虚反射多次波干扰,还提高了地震数据信噪比和分辨率,为后续联合反褶积和偏移成像等处理提供了高保真的上行波场和下行波场数据。合成数据和实例数据说明了所提方法的有效性和实用性。

The separation of the up-going and down-going wavefields is a key step in the data processing of dual-sensor seismic data.Aiming at the disadvantage that the up-going wavefield separated by conventional methods contains the down-going wavefield,and the down-going wavefield contains the down-going wavefield,that is,the up-going and the down-going wavefields can not be separated completely,this paper introduces three energy matching factors and four wavefield separation contribution factors.Three energy matching factors are the energy matching factor of dual-sensor data,the up-going wavefield energy matching factor of the down-going wavefield,and the down-going wavefield energy matching factor of the up-going wavefield.Four wavefield separation contribution factors are the up-going wavefield contribution factor of the hydrophone data,down-going wavefield contribution factor of the hydrophone data,the upgoing wavefield contribution factor of geophone data,and down-going wavefield contribution factor of the geophone data.The up-going and down-going wavefield separation equations are established.The optimal energy matching factors of the up-going and down-going wavefields of dual-sensor seismic data are computed and determined by an iteration algorithm.Then the wave field separation contribution factors are directly calculated to realize the complete separation of the up-going from down-going wavefields of dual-sensor seismic data.The separated up-going wavefield data not only eliminates the ghost multiple interferences,but also widens the effective frequency band.The signal-tonoise ratio and resolution of the seismic data are improved too,and the high-fidelity up-going and down-going wavefields are provided for subsequent joint deconvolution and migration imaging processing.The effectiveness and practicability of this method are illustrated by synthetic and real data examples.