Vertical seismic profile S-S imaging with vertical vibrators

The vertical vibratory source is ubiquitous in land P-P seismic acquisition. However, the source may be observed to produce a rich field of other (S-wave-like) modes that can be identified and processed to exploit the characteristics of the S wavefield at no additional acquisition cost. S-waves lack gas sensitivity and have complementary characteristics when compared to P-wave data in response to the same stratigraphy. Sh modes are decoupled and tend to have less interference, enhancing their S/N and facilitating processing. Direct S-wave arrival times can be inverted for velocity, leading to the construction of Vp/Vs and other attributes. This paper presents an example of combined P- and source-generated S-wavefield processing through imaging for zero-offset and offset vertical seismic profiles (VSPs).