Velocity is one of the fundamental data obtained from seismic and it is
the direct behavior of the solids and fluids in lithosphere. Here we
present an analysis of the derivative gradient of seismic velocity which
can help identify the featured boundary of favorable petroleum
accmulations such as sedimentary facies boundary, faults, and flow unit
edges. The derivative gradient can be calculated both horizontally and
vertically, thus it can help discriminate favorable targets in
three-dimensional. We find the application of derivative gradient to
detect or enhance edge is relatively mature in gravity and geomagnetic
analysis but rarely mentioned in seismic nor in petroleum exploration.
We believe we can make better use of the seismic velocity data by this
means as it is quite efficient in pinpointing the favorable petroleum
targets in subsurface with precisions of tens-of-meter scale, depending
on the horizontal resolution of seismic survey.