地震数据表征:速度与加速度

Seismic data description:velocity or acceleration

陆上地震勘探中地震信号表现为地表的机械振动,速度和加速度是常用的表征物理量。本文分析了由震源激发有效信号的加速度、速度的幅度和频带范围,研讨了地震检波系统对地表振动的记录和改造作用。认为成熟的不同类型(速度/加速度)工业用检波器拾取的地震数据在对地震勘探有意义的范围内能可靠地相互转换、互为印证,以20DX为代表的动圈式检波器在现今处理框架下仍是"高效率检波器";同时,剖析了不同类型检波器数据比较方法的物理、数学合理性,指明了当前常用方法的局限性;最后,列举后续处理过程中选择不同表征物理量对计算结果有重要影响的六方面因素,强调在实际选择表征物理量时应做更多的基于地震数据地球物理属性的理论分析及试验验证,不宜仅由简单的生产结果比对进行证明。

In the land seismic survey,mechanical vibration of the ground are recorded as seismic data.Normally this data is described in velocity or acceleration,two are common forms used for onshore petroleum exploration.We discuss in the paper the meaningful frequency band and amplitude range of onshore seismic survey in velocity and acceleration,and analyze various factors involved in the seismic recording system(sensor,sensorground coupling,and seismograph).In land seismic survey,commonly used sensors are geophones,among which the model 20 DX geophone is very popular.Another one is MEMS,an acceleration sensor,Sercel's DSUs for instance.We review velocity and acceleration of typical sensors,compare their consistency of data,and analyze recorded data reasonability and validity with physical and numeric results.Finally more geological and geophysical factors should be taken into accounts carefully when selecting the description domain of seismic data.