GX Technology’s Reverse Time Migration (RTM) is a solution for exploration in subsalt prospects. RTM is not a new concept, but barriers to the introduction of the technology have been

A subsalt image generated with conventional technology (top) shows poor imaging of salt flanks and subsalt structures. A subsalt image generated with RTM technology shows significant improvement in imaging salt flanks, even beneath the salt. (Images courtesy of GX Technology)
formidable throughout the industry due to the complexity of the algorithm and the amount of compute power required to run the process. GXT’s RTM algorithm in com-
bination with preprocessing, dedicated computational power and better handling of anisotropic conditions have turned RTM into a tool that is making an enormously positive impact in the imaging of salt flanks and subsalt for exploration and development programs.
Current migration methods face limitations in the presence of complex, steeply dipping reflectors such as those found on salt flanks. RTM overcomes these constraints, enabling structures with dips greater than 90° to be properly imaged. RTM works by running the wave equation forward in time for the source and backwards in time for the receiver. RTM properly propagates the wavefields through the most complex velocity regimes, including subsalt, for structures having very steep dips.