利用陆上三分量数据改善气云区构造成像
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摘要
针对柴达木盆地东部三湖地区涩北气田构造部位的气藏部分泄漏造成纵波同相轴下拉,振幅、频率变低,成像效果明显变差,无法准确描述构造形态等现状,有必要提高气云区构造成像精度,区分真假含气异常。为此在该区进行了炸药震源激发、数字三分量检波器接收的多分量勘探试验,完整记录了各种波场。对比各种记录可以看出,转换波反射特征明显,其中水平分量面波区内还有横波反射。本文利用VSP及地面三分量资料对这种波场进行了详细的分析,对多分量数据的水平分量进行预测反褶积,较好地压缩了地震子波,消除了鸣震;以基于三分量微测井资料建立的表层模型为基础,借助转换波检波点校正量的求取,最终得到准确的横波炮检点静校正量,使转换波与横波均得到了较好的成像,横波成像极大地提高了气云区的成像精度。
In view of issue in the structural position of Sebei gas field in Sanhu area of the east of Qaidam Basin that the natural gas leaking resulted in P-wave events push-down,weakening the amplitude and lowering the frequency,making the imaging result obvious deterioration and incapable to accurately describe the structural attitude,it is necessary to improve the imaging precision in gas chimney area and distinguish between true and false gas-bearing anomaly. For that reason,the multi-component exploration experience with explosive source for shooting and 3-C digital receiver for receiving was carried out in that region,which gained a complete record of various wavefields. Ii is seen from the correlation between various records that the feature of PS-wave reflections is obvious,among which there are PS-wave reflections in plane wave area of horizontal component. The paper analyzed in detail the wavefield by using VSP and 3-C land seismic data,carried out predictive deconvelution for the data of horizontal component in multi-component seismic data,better compressing seismic wavelet and eliminating ringing; based on near-surface model created by 3-C uphole survey and in the aid of computation of statics of PS converted wave at receiver,the accurate S-wave statics at shot and receiver points ware finally obtained,making the PS converted wave better imaging that greatly improved the imaging precision in gas chimney area.
In view of issue in the structural position of Sebei gas field in Sanhu area of the east of Qaidam Basin that the natural gas leaking resulted in P-wave events push-down,weakening the amplitude and lowering the frequency,making the imaging result obvious deterioration and incapable to accurately describe the structural attitude,it is necessary to improve the imaging precision in gas chimney area and distinguish between true and false gas-bearing anomaly. For that reason,the multi-component exploration experience with explosive source for shooting and 3-C digital receiver for receiving was carried out in that region,which gained a complete record of various wavefields. Ii is seen from the correlation between various records that the feature of PS-wave reflections is obvious,among which there are PS-wave reflections in plane wave area of horizontal component. The paper analyzed in detail the wavefield by using VSP and 3-C land seismic data,carried out predictive deconvelution for the data of horizontal component in multi-component seismic data,better compressing seismic wavelet and eliminating ringing; based on near-surface model created by 3-C uphole survey and in the aid of computation of statics of PS converted wave at receiver,the accurate S-wave statics at shot and receiver points ware finally obtained,making the PS converted wave better imaging that greatly improved the imaging precision in gas chimney area.
引文
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[2]Li X Yet al.Compensating for the effects of gas clouds on C-wave i maging:A case study from Valhall.The Leading Edge,2001,20:1022
[3]Stewart R Ret al.Converted-wave seismic exploration:Applications.Geophysics,2003,68(1):40～57
[4]He Hanyi et al.Multicomponent seismic explorationin Yinggehai Basin.The Leading Eage,2002,914～920
[5]王西文等.三湖地区地震资料处理中的静校正方法研究.石油地球物理勘探,2007,42(5):572～580
[6]Li Y.A new method for converted wave static correc-tion.Expanded Abstract of72nd SEG Meeting,2002,979～981
[7]Thomsen L.Converted-wave reflection seismology over anisotropic,inhomogeneous media.Expanded Ab-stracts of68th SEG Meeting,1998,2048～2051
[2]Li X Yet al.Compensating for the effects of gas clouds on C-wave i maging:A case study from Valhall.The Leading Edge,2001,20:1022
[3]Stewart R Ret al.Converted-wave seismic exploration:Applications.Geophysics,2003,68(1):40～57
[4]He Hanyi et al.Multicomponent seismic explorationin Yinggehai Basin.The Leading Eage,2002,914～920
[5]王西文等.三湖地区地震资料处理中的静校正方法研究.石油地球物理勘探,2007,42(5):572～580
[6]Li Y.A new method for converted wave static correc-tion.Expanded Abstract of72nd SEG Meeting,2002,979～981
[7]Thomsen L.Converted-wave reflection seismology over anisotropic,inhomogeneous media.Expanded Ab-stracts of68th SEG Meeting,1998,2048～2051
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