Reverse Time Migration (RTM)
Traps against steeply dipping geology can be extremely prolific and capable of being drained with relatively few high-rate wells. However, current migration methods face limitations in the presence of complex, steeply dipping reflectors such as those found on salt flanks. Reverse time migration (RTM) overcomes these constraints, enabling structures with dips greater than 90 degrees to be properly imaged.
Enhanced RTM Approach
Although RTM is not a new concept, its application has been limited due to the algorithms' power needs, cost, and turnaround time. Our RTM method was developed by matching highly sophisticated algorithms with currently available computational power, resulting in an improved and economical solution for imaging complex subsalt prospects. We have applied the technique extensively worldwide, including the Gulf of Mexico, North Sea and offshore West Africa.
Wide Azimuth Reverse Time Migration
Wide azimuth surveys have acquisition geometries that are ideally suited for RTM. ION's RTM has the ability to image complex raypaths, including prismatic waves (double-bounce events), which may be a key attribute in resolving target prospects and the positions of those prospects. In addition, our RTM code supports VTI, TTI and higher order orthorhombic anisotropy. In areas where visco acoustic conditions may be encountered, ION has also developed an efficient Q RTM to handle spatial variations for higher fidelity imaging results.
High Frequency RTM
Our High Performance Computing (HPC) optimized algorithm eliminates any dependency on additional hardware accelerators, making our reverse time migration easily extensible to higher frequencies (up to 125 Hz 3D) even when migrating larger pre-stack volumes. This frequency extension allows the geophysicist to see subtle stratigraphy associated with complex geologies that could be valuable even in land projects.
Benefits of ION's RTM Offering
- Higher fidelity subsurface imaging
- Images both the steep sides of salt bodies and underneath them, regardless of the dip and rugosity at the top
- Yields more accurate models that significantly improve the final sub-salt image
Options to match unique geologic challenges (efficient runtime, high frequency, Q attenuation, anisotropic mediums)
- Reducing Sub-salt Uncertainty - North Sea RTM Case Study - EAGE Technical Paper (PDF)
- Attenuation compensation in viscoacoustic reverse time migration- SEG Technical Paper (PDF)