Changes

With at least two time-lapse surveys in hand, the differences in the successive images ([[:file:cross-borehole-tomography-in-development-geology_fig3.png|Figure 3]]) should relate to changes induced in the reservoir by the process, all other factors being constant.

With at least two time-lapse surveys in hand, the differences in the successive images ([[:file:cross-borehole-tomography-in-development-geology_fig3.png|Figure 3]]) should relate to changes induced in the reservoir by the process, all other factors being constant.

Single tomographic images, however, are often difficult to interpret. Changes in the observed seismic velocity field across the reservoir may be due to the combined effects of lithology, pore fluids, and the physical state of the reservoir. Often geological stratification is easily discernible ([[:file:cross-borehole-tomography-in-development-geology_fig4.png|Figure 4]]) due to the contrast in seismic velocities characteristic of different types of rocks The results of faulting and other structural features in the reservoir can also sometimes be seen, when associated with a sufficient contrast in seismic velocities.

Single tomographic images, however, are often difficult to interpret. Changes in the observed seismic velocity field across the reservoir may be due to the combined effects of lithology, pore fluids, and the physical state of the reservoir. Often geological stratification is easily discernible ([[:file:cross-borehole-tomography-in-development-geology_fig4.jpg|Figure 4]]) due to the contrast in seismic velocities characteristic of different types of rocks The results of faulting and other structural features in the reservoir can also sometimes be seen, when associated with a sufficient contrast in seismic velocities.

==Applications==

==Applications==