Go to:

  previous
  next
  story

The Geophysical Corner is a regular column in the EXPLORER, produced cooperatively by the AAPG Geophysical Integration and SEG Interpretation committees, and edited by M. Ray Thomasson. This month's column is titled "VSP -- The Link Between Geology and Geophysics."

VSP Links Geology, Geophysics

By RONALD C. HINDS and RICHARD KUZMISKI

Editor's note: Hinds is a senior geophysicist for PanCanadian Resources, Calgary, Canada; Kuzmiski is responsible for VSP and acoustic log processing at Computalog, Calgary.

Click on the figure below to view greater detail.

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 6. The first break event is found on both the X and Y data. The wavelet is sometimes more consistent on one compared to the other. This is due to the tool rotating in the borehole between tool relocations. The first break event in (A) is the primary downgoing P- or compressional wave. A mode-converted SV or shear event is highlighted in blue in panels (A) and (C). This event dips in a different direction than the downgoing P event because of its slower velocity. In panel (C), the P-wave up- and downgoing events are easily recognized. Note that there is a hyperbolic shaped event near the bottom of the data panel which could be a refracted shear at the 750 m interface.