Kirchhoff & Wave Equation Depth Imaging
SIGMA³ is a leading provider of Depth Imaging Software and Services to the oil and gas industry. With our advanced imaging technology, we help oil and gas companies visualize accurately 3D earth structures and reduce drilling risks associated with oil and gas exploration. Companies that use our Depth Imaging Technologies lower the cost of production, provide faster delivery of oil and gas to the marketplace, and tap oil and gas from ever more challenging plays.
The advanced imaging group, with its roots in depth imaging technology stemming from the Stanford Exploration Project, maintains a strong R&D group specializing in imaging technology and offering collaborative projects with partners to improve and develop imaging technologies for the future.
Anisotropic Reverse Time Migration is probably the most intuitive wave-field continuation migration method in the industry. Both the source wave-field and the recorded wave-field are continued along the time axis, the source wave-field is propagated forward in time, whereas the recorded wave-field is propagated back in time, thus the name. The image is formed by cross-correlating the two wave-fields, and evaluating the correlation at zero lag.
The kernel of RTM consists of a finite-difference code which models the acoustic wave propagation in three-dimensional media. The finite-difference formulation solves the two-way wave equation. RTM is implemented with domain decomposition which distributes the simulation grid for a single shot across multiple processors. Because each processor can operate on just a portion of the total simulation grid, the amount of memory, disk space, and computation per processor can be greatly reduced providing quick delivery.
ShotPRO™ – Anisotropic Shot Domain Wave Equation Migration is a Wave Equation migration technique where individual shot gathers are migrated to create an image of the Earth. This method propagates a source and a receiver wave-field (the shot gather) in the subsurface with a propagator based on the one-way or two wave equation followed by an imaging condition. This method handles wide azimuth data naturally and is particularly suited for land or ocean bottom surveys. Output of 3D angle gathers is supported.
FastPRO™ – Anisotropic Common Azimuth/ Narrow Azimuth Wave Equation Migration is a double square root Wave Equation Migration coded specifically for common azimuth and narrow azimuth data. As its name implies it is a very fast streamline algorithm, which is the workhorse for suitable marine 3D streamer surveys providing a powerful wave-equation solution for multi-pathing. It provides domain decomposition for large volumes.
K3D – Anisotropic Pre-Stack Time and Depth Migration is recognized as the most flexible Kirchhoff method of imaging prestack 3D seismic data. 3D prestack migration of surface seismic data is the ultimate tool for imaging the earth's subsurface in areas of complicated geological structure. Kirchhoff migration is particularly appropriate for 3D prestack data because of its flexibility in imaging irregularly sampled data and for its relative computational efficiency.
Kirchhoff migration images seismic data by approximately solving the wave equation with a boundary integral method. The acoustic reflectivity at every point of the earth's interior is computed by summing the recorded data on multi-dimensional surfaces.