科研之友
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摘要
In interpretation of seismic data the resolution and smoothness of the envelope of the seismic trace is an important property to have. This paper introduces a new method of envelope generation for seismic traces that is based on the concept of normalized total gradient (NTG) that found many useful applications in interpretation of potential field data and is considered in that field of study to be better resolved and smoother than envelopes obtained using the well known complex trace concept based on Hilbert transform. The NTG method defines a seismic trace by finite Fourier sine series. It then converts the seismic trace into an analytical trace in a manner similar to complex seismic trace analysis. As this trace is made of partial derivatives of a new function defined from the trace itself it is indeed a gradient vector and its envelope is therefore called "total gradient". The division of the total gradient by its average over time forms the "normalized total gradient" (NTG).
In this study we investigate in general the use and effectiveness of the NTG method to calculate envelope of seismic data. Thereby, we particularly consider the importance of the choice of parameters to obtain stable results. It then compares the results of the NTG method with those obtained from the Hilbert transform method for synthetic as well as field data. Although these two methods are closely related, it is shown that only for an adequate choice of parameters do the envelopes obtained by using the NTG method are better resolved and smoother than those are obtained using the Hilbert transform. The NTG method can therefore be used as a quantitative tool in separating individual reflections from those which are made of interfering composite reflections since it clearly reveals local maximum points of the reflections.
- 出版日期2010-6
