Time Lapse

One application for this procedure is assessing the temporal variation of time-lapse images. When seismic data are acquired in the same location at different times, disparity estimation can be used to visualize changes in the subsurface caused by compaction or fluid flow. This was done with three migrated images from the Duri Field in Indonesia that were collected over a 20 month period in the Duri Field of Indonesia. The original images Lumley (1995) are shown in figure  with the magnitude of the disparity between the images. The magnitude of the disparity offers very little information for this application. The vector representation, displayed in figure  with each vector scaled by 2, however, better accentuates the change providing useful information. Although it is hard to distinguish by looking at the migrated images, there are subtle changes that can be seen. The left edge of the hump near the center of the image increases slope from the left panel of figure to the right. This slight change is detected by the image disparity algorithm and can be seen with downward pointing arrows near that have been circled in figure , corresponding to the left slope of the hump. This may be related to the insertion of an observation well near that location. The arrows do distinguish changes throughout the image, but it is very difficult to tell if these correspond to real changes, noise, or some slight variation caused by a change in acquisition.

 

lapse
Figure 6 Two images from the same location at Duri Field at different times. Left:The magnitude of the change relative to the first image.

 

veclapse
Figure 7 The disparity as a vector plot, sub-sampled by 2 in the x direction and 12 in the y direction.