起伏地表煤田地震资料静校正

Static corrections for coalfield seismic data in relief surface areas

由于地表起伏和近地表结构变化产生的静校正问题严重影响了煤田地震资料的成像质量.为此,首先利用低速带分片拟合的广义线性反演技术进行折射波静校正,解决长波长静校正问题和部分短波长静校正问题,然后,利用叠加能量最大静校正技术进一步解决剩余静校正问题,最后,利用非地表一致性剩余时差校正技术,解决速度和射线等误差引起的非地表一致性剩余时差问题.实验结果表明,在以串连的方式应用了三种校正方法之后,在共炮点道集上,折射波同相轴的线性形态得到了恢复;在动校正后的共中心点道集上,煤层反射的双曲线同相轴被拉平;在叠加剖面上,煤层反射的信噪比得到了改善.

The imaging quality of coalbed seismic data is greatly degraded by static time shift resulted from relief surface and structural variation of near-surface layers. To solve the problems, firstly, the generalized linear inversion refraction static correction based on piecewise fitting of weathered zone is applied to correct long wave-length statics and a part of short wave-length statics. Then, the residual statics are further corrected by the stack-power maximization static correction method. Finally, the non-surface-consistent residual moveout correction is used to correct the residual moveouts resulted from the errors of velocity and ray path. The processing results show that after the application of three correction methods in series, the linear refraction events are recovered in shot gathers, the hyperbolic events of coalbed reflection are aligned, and the signal to noise ratio of coalbed reflection is improved in the stack section.