``Squeeze'' effect

The first effect to address is the ``squeeze,'' where P_h coverage is reduced, especially at higher frequencies. This is mainly a function of CMP trace sampling. Specifically, it is a function of half-offset wavenumber and frequency. P_h can be calculated by a radial trace transform in ($\omega$,k_h) domain using equation (2):

$$P_h \; = \; \frac{k_h}{\omega} \;,$$ (2)

where the maximum k_h is given as $\frac{1}{2 \Delta h}$. So if we, sample twice as much in half-offset, the maximum k_h doubles, and our maximum P_h increases, as seen in Figure 2.

 

kh_compare Figure 2 Two amplitude plots after migration. Bottom has half the $\Delta h$ of the top.