DDR: The Technology Of Simultaneous Wave Field Analysis And Velocity Model Reconstruction

The technology of VSP data processing by means of DDR (Dynamic Decomposition of the<br>wave-field and Reconstruction of the media) technique consists of several procedures:<br>1. Construction of the first approximation to<br>model as a result of kinematical inversion of travel<br>times and polarizations for visually correlated<br>events in original data.<br>2. The synthetic wave parameters are<br>calculated by ray-tracing method for strongest<br>event.<br>3. The estimation of the form of a wave along<br>calculated arrival times-graph with use of designed<br>distribution of amplitudes and polarization is<br>carried out.<br>4. The located wave is subtracted from an<br>initial wave field and is projected to the points of scattering on the image section. The waves of<br>various types from the same point of boundary are stacked with weights proportional to their original<br>amplitude. The process is repeated for all types of waves and all boundaries until all regular events<br>are subtracted and projected on section. Not only primary waves, but also multiples may be used in<br>the process. After imaging the basic model can be corrected and the process may be repeated until<br>the image will correspond to model with necessary accuracy.