Application of the Reverse Time Migration in Acoustic Reflection Imaging Logging

Reverse time migration (RTM), which has the ability to migrate any type of multiples (surface and internal) to their correct location in the subsurface, can handle multi-pathing, image turning waves and handle steep dips. This paper, for the first time, proposes RTM in the borehole for near borehole structure imaging. In forward simulation of the source wave field and backward extrapolation of the received wave field, the high order staggered grid finite difference method is applied. The cross-correlation imaging condition divided by the receiver illumination is used to get the imaging result. In addition, the differences between RTM in seismic exploration and in the borehole are analyzed, based on which, the RTM is modified to include the borehole environment. Finally, imaging results for the synthetic fracture model and cavity model, as well as real data from both the laboratory water tank and oilfield demonstrate the validity and capability of the modified RTM.