TOMOXä is designed for
performing cross-hole and VSP traveltime tomography. Its rapid computation
capability allows you to reconstruct the velocity structures real time in a
production environment. With eight modules, you are able to start with the
seismic traces, then generate and interpret image solutions. It also allows
you to view well-logging data. You may apply the log information to
constrain tomography or compare a tomographic solution with the well-logging
data. Tomographic imaging can directly provide you with the structure
solution that you need to find oil and gas reserves, or for any other
seismic data processing.
Cross-hole seismic survey provides ideal raypath coverage
for imaging the seismic velocity structures between two close wells. However,
applying any conventional "ray-shooting" traveltime calculation technique
for cross-hole imaging requires significant computer power. Thus, cross-hole
imaging used to be very difficult for real application. Tomographic method
in the software applies a rapid wavefront raytracing technique for
simultaneous time and raypath calculation. Its computation time is
independent of the number of receivers. In addition, it analyzes velocity
structures prior to raytracing and inversion for optimizing the computation.
These improvements and the new techniques enable cross-hole imaging to be
completed in minutes or even seconds on a PC.
VSP is a low-cost seismic survey in depth.
VSP imaging helps to extend the seismic velocity structures laterally from a
single well point. Well logging results often present local velocity
measurements only, while VSP tomographic imaging with the well-log
constraints can resolve near-well velocity structures more accurately. Since
VSP tomographic imaging is fast, and uses the first-arrival times only, it
can always provide a first and quick look at the subsurface regardless of
how complicated the down-going and up-doing multiples might be. The Rapid
wavefront raytracer can be used in planning VSP surveys to determine source
offsets for the required subsurface coverage. It can be also used as an aid
in understanding the VSP traveltime responses of geologic features such as
dip, faults, and diffractions.