3D Spectral Element Modelling for Acoustically Sensing a Well from a Nearby Well

Single well imaging using full-waveform sonic log data, a known technique for locating fractures and mapping bed boundaries, can also be used to locate boreholes from nearby observation wells. For this technique, generating accurate seismograms including not only reflected waves but also borehole-guided waves is of paramount importance for both the prejob planning phase and for testing and validating the processing sequence in the imaging phase. We implemented a 3D GPU-based spectral element code, which is well suited for this type of modelling in terms of accuracy and performance. With the spectral element method modelling, we were able to reproduce, qualitatively, the case of a vertical borehole acoustically sensed by a nearby horizontal well.