Contents
What is phase wavelet?
Consider a signal with a zero-phase spectrum. Such a time-domain signal is called a wavelet. A wavelet usually is considered a transient signal, that is, a signal with a finite duration. It has a start time and an end time, and its energy is confined between these two time positions.
What is seismic source wavelet?
The seismic wavelet is the link between seismic data (traces), interpretations and the geology (reflection coefficients). It must be accurately known (estimated or measured) and quantified in all stages of the seismic cycle (from modelling, acquisition, processing, interpretation, inversion and reservoir work).
What are the characteristics of wavelets?
Wavelet
- A wavelet is a wave-like oscillation with an amplitude that begins at zero, increases, and then decreases back to zero.
- In continuous wavelet transforms, a given signal of finite energy is projected on a continuous family of frequency bands (or similar subspaces of the Lp function space L2(R) ).
What is the phase of seismic data?
Phase in seismic data is simply known as the lateral time delay in the start of a reflection recording, and because it is amplitude-independent, phase can be used as a good continuity indicator in poor reflectivity areas in the seismic data with a higher sensitivity to reflection discontinuity caused by pinch outs.
What is bubble effect seismic?
1. n. [Geophysics] In marine seismic acquisition, the gas bubble produced by an air gun oscillates and generates subsequent pulses that cause source-generated noise. Careful use of multiple air guns can cause destructive interference of bubble pulses and alleviate the bubble effect.
How is seismic data processed?
There are three primary steps in processing seismic data — deconvolution, stacking, and migration, in their usual order of application. Figure 1.5-1 represents the seismic data volume in processing coordinates — midpoint, offset, and time. Deconvolution acts along the time axis.
How do you know if a system is a minimum-phase?
In control theory and signal processing, a linear, time-invariant system is said to be minimum-phase if the system and its inverse are causal and stable.
What is the definition of a zero phase wavelet?
Such a wavelet is called zero phase. In fact, the wavelet was synthesized using the zero-phase sinusoids of equal peak amplitude. A zero-phase wavelet is symmetric with respect to zero time and peaks at zero time. Figure 1.1-12 shows the result of applying a linear phase shift to the sinusoids in Figure 1.1-11.
Can a zero phase filter produce no phase distortion?
A zero phase filter produces no phase distortion. See Figure P-2 and phase characteristics. 2. A wavelet symmetric about zero time. It is the shortest possible wavelet for any given spectrum. The SEG standard for display of a zero-phase wavelet is shown in Figure P-6 .
What kind of signal has zero phase lag?
All of these sinusoids have zero-phase lag; thus, the peak amplitudes align at t = 0. The time-domain signal on the trace identified by an asterisk in Figure 1.1-11 is synthesized by summing all these sinusoids — a process described by inverse Fourier transform. Such a time-domain signal is called a wavelet.
How do we convert the seismic trace wavelet to zero phase?
What you can do is to first approximate the real wavelet with a simple zero-phase phase wavelet extracted from the autocorrelation of the seismic data (or you can use a Ricker wavelet of a reasonable dominant frequency if you want) and make a synthetic seismogram at the well.