摘要
采集脚印是地震勘探中的固有不利因素,给地震资料解释带来假象。采集脚印可以通过野外采集参数或者观测系统优化等方法进行压制,但往往成本较高。室内的叠后采集脚印压制方法因叠加模糊了观测系统的因素,信号的保真度低。为此,给出了一种OVT道集时间切片相干加强的采集脚印压制方案,即先做叠前5D数据规则化,后进行OVT叠前时间偏移,再校正OVT叠前时间偏移“蜗牛”道集的方位各向异性时差,以消除方位各向异性时差的影响;然后把“蜗牛”道集分选成单次覆盖的单个OVT道集,并按照采样时间切取OVT道集的时间切片,在时间切片上通过相干加强的方法压制采集脚印;最后把采集脚印压制后的数据反分选回“蜗牛”道集。实际数据应用表明:采集脚印在单次覆盖时间切片上的特征较时间偏移剖面上更为明显,规律性更强,与常规的叠后频率—波数域限波方法相比,该方法能更好地保持地震信号振幅的道间相对关系;在某浅海OBC采集数据的采集脚印压制中取得了明显的效果。
Acquisition footprints are inherent attributes of seismic exploration,causing illusion to seismic data interpretation.They can be suppressed by optimizing field acquisition parameters or geometry,but the cost is often too high.Since the indoor post-stack methods to suppress acquisition footprints blur the geometry factor due to stacking,the signal fidelity is low.Thus,this paper proposes a technical scheme for acquisition footprint suppression based on time slice coherent enhancement of OVT gathers.The pre-stack 5D data regularization and OVT pre-stack time migration(PSTM)are conducted successively.Then azimuth anisotropic time difference based on the OVT snail gather of PSTM is corrected to eliminate its effect.Meanwhile,the snail gathers are sorted into a single OVT gather which has only one fold and then the time slice is cut according to the sampling time for suppressing acquisition footprints by time slice coherent enhancement.Finally,the data after suppressing the footprints is reversely sorted back to the snail gathers.Actual data application shows that the characteristics of acquisition footprints on time slice with one fold are more obvious than those on the time migration profile,with stronger regularity.Compared with the commonly used methods of wave limiting in the post-stack frequency-wave number domain,the proposed method can maintain the relationship among channels of seismic signal amplitude and yields notable results in acquisition footprint suppression of OBC data collected in a shallow sea.
作者
张一波
刘浩
董庆宇
张红军
于明
杜厚余
ZHANG Yibo;LIU Hao;DONG Qingyu;ZHANG Hongjun;YU Ming;DU Houyu(Oversea Business Department,Geophysical Research Insititute,BGP Inc.,CNPC,Zhuozhou,Hebei 072751,China)
出处
《石油地球物理勘探》
EI
CSCD
北大核心
2023年第S01期12-16,共5页
Oil Geophysical Prospecting
基金
中国石油天然气集团公司重大科技项目“海外复杂领域物探处理关键技术研究”(2021DJ3401)资助。
关键词
采集脚印
5D数据规则化
OVT道集
时间切片
相干加强
acquisition footprint
5D data regularization
OVT gather
time slice
coherent enhancement
