摘要
根据我们在不同的技术要求和不同的地震地质条件下进行的工作,本文讨论了垂直地震剖面工作中地震波的激发和接收,以及薄层和断层的探测问题,得出了四点结论:1.可控震源及浅水中爆炸能较好地保持地震波激发条件的一致性;2.小口径的井下检波器通用性好,下井时所遇流体的阻力小,且在井中流体上涌时能降低记录的噪音水平;3.垂直地震剖面资料也证明了薄层顶面及底面的合成反射波的主要频率高于入射波的频率;4.直达波穿过断层后高频成份显著减弱。
Abstract
Vertical seismic profiling is a new exploration method. It may be used to resolve some complicated geophysical problems which can't be resolved by surface seismic exploration, and has good perspective of application.According to the VSP works carried out under different technological requirements and different seismogeological conditions, in this paper we discuss the problems of generation and reception of seismic waves, and detection of thin layers and faults in VSP works. We obtain the following ideas:1. within the three types of seismic sources which we have used, the vibrators and explosions in shallow waters can satisfactorily preserve the identity of wave generation onditions;2. The downhole detector with small outer diameter can be in common use, and can minimize not only the resistance of the fluid when it is letting down along the wall of the borehole, but also the noise lever of records when the fluid is welling up;3. VSP data have also proved that the dominant frequency of composite reflections from the top and the bottom of a thin layer is usually greater than that of incident waves;4. The obvious attenuation of high frequency component of direct waves penetrated the fault, can be used as an indication of the presence of fault.
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