Seismic exploration · add or remove the trap

Illustrative two-dimensional geometry. Trap ON represents an anticlinal structural closure in cross-section, assuming a suitable seal; three-dimensional closure, charge and hydrocarbon presence are not established. OFF makes the reflector horizontal, not a universal absence of all trap types.

Rays use a single constant acoustic velocity above one reflector. Reflection points minimize the sum of source-to-reflector and reflector-to-receiver distances over the profile. Travel time is total ray length divided by velocity. Synthetic traces use an illustrative 18 Hz Ricker wavelet with fixed amplitude. This is a pulse representation, not a raw vibroseis sweep. Shown upper layer bands are visual only: refraction, multiple scattering, impedance inversion and fluid effects are omitted. Animation runs at one fifth of real wave speed for visibility; trace axes show physical seconds.

References: US EPA · Seismic Reflection; SLB · Anticlinal trap. All numeric inputs are illustrative.