Our process eliminates the difficulties encountered by standard depth-domain 2D and 3D VSP data processing procedures.  Most companies attempt to use Pre-Stack Depth Migration (PSDM) to generate a reflection image from 2D or 3D VSP data. While Pre-Stack Depth Migration provides a convenient way to handle the source-receiver geometry of VSP data it imposes the burdensome requirement of determining an extremely precise 3D anisotropic interval-velocity-with-depth field. Determination of a velocity field for 3D VSP or even 2D VSP depth migration is very time consuming, often taking 6-10 months to finalize.  This is long after the value of the data could have been maximized for the client, and even after long time delays, the results are often disappointing.​

Our time-domain approach eliminates the problems of using only Pre-Stack Depth Migration for 2D and 3D VSP processing. We have developed and patented a wave-equation datuming algorithm based on well-proven wave theory to upward continue data recorded in the borehole to the topographic surface of the earth (Figures 2 and 3). The data transformation from the borehole to the surface requires no knowledge of near-surface statics or of the velocity field.  The method only requires use of measured first arrival times that are recorded as a normal part 2D or 3D VSP data acquisition.​

Once the wavefield recorded in the borehole has been upward continued to the topographic surface of the earth the data can be treated as surface seismic data. We are then able to process the data as surface seismic data, making use of its well-developed tools, most importantly surface-consistent residual statics and NMO analysis. Thus, we can process even the largest of marine or land 3D VSP datasets in a time frame that is similar to surface seismic datasets.

The 2D and 3D seismic reflection images resulting from application of our method are naturally in the time-domain and overlay surface seismic sections but typically contain two or more times the frequency content of surface seismic data. The resulting images can be converted to depth with an appropriate interval velocity field that can normally be at least partially derived from the VSP data.