A borehole source

As a second modeling example I used a vertical component source placed in a bore hole. The medium is homogeneous except the borehole, which is fluid filled and three extended point scatterers. In the first case I used an impulsive source, in the second case I used a continuous source, as would have been produced by a drill bit. There is a free surface at the top of the medium and resonances occur in the borehole. Clicking on the figure buttons will bring up movies showing wave propagation in that medium.

 

scatter Figure 8 Medium model with a fluid filled borehole and three extended point scatterers.

 

xseis.imp Figure 9 Horizontal component seismogram recorded at the surface using an impulsive source.

 

zseis.imp Figure 10 Vertical component seismogram recorded at the surface using an impulsive source.

 

xseis.sin Figure 11 Horizontal component seismogram recorded at the surface using a sinusoidal source.

 

zseis.sin Figure 12 Vertical component seismogram recorded at the surface using a sinusoidal source.