The members of the OGF Imaging team bring decades of experience from projects around the world including North & South America, West Africa, the North Sea, and Southeast Asia in marine, land, and transition zone environments. Additionally, members of the OGF team have years of experience with Japanese basins, bringing a combined 50+ years’ experience with 70+ Japanese projects among members to Tokyo. OGF Imaging also has the full support of PGS Imaging and the full SPArk imaging suite of applications, providing clients with the top in class imaging software. Our data center located in Japan has all the computing power needed to provide reliable imaging solutions quickly to clients both in Japan and internationally.
Tansa Operations Geophysics works closely with the onshore imaging team to deliver products and can deliver high quality fast track products directly after acquisition to enable a rapid start to interpretation.
The bandwidth of marine towed streamer acquisition is reduced by the presence of ghosts. However, OGF technology can recover the frequencies lost to ghosts. Two types of method are offered to address the ghosts – acquisition-based and processing-based solutions.
OGF’s acquisition-based solution uses Tansa’s dual-sensor Geostreamer technology to completely recover the energy at the receiver notches. This energy is otherwise lost in single sensor acquisition.
OGF also utilizes a processing-based solution to model the ghost functions, for which compensation can then be applied. There are limitations to this technology as there are many assumptions to the properties of source and to the sea state. Processing-based deghosting solutions can be applied to both multi-sensor acquisition and conventional streamer data. This means that the benefits of modern technology can be applied to vintage datasets via reprocessing, bringing a new perspective to older data.
OGF offers a complete set of deghosting solutions comprising both acquisition-based and processing- based techniques or a combination of both.
For source designature, OGF utilizes the BOSS+ (Bandwidth Optimized Signature Solution) workflow developed by PGS. In this process the ghost-free far field signature is both de-bubbled and zero phased. No deconvolution is used in this process, enabling OGF to preserve the full bandwidth of the seismic data. This process is applied as a 1D filter, and an additional 3D correction can also be applied to correct for variation in emergence angle.
The SPArk processing package offers a complete denoise techniques to effectively reduce the presence of unwanted noise energy while preserving amplitude characteristics.
OGF offers a full suite of 3D pre-stack demultiple solutions for any range of water depths and acquisition geometries. The solution provided depends on the challenges presented by the data and the requirements of the client.
3D wavefield extrapolation-based Surface Related Multiple Elimination (SRME) is performed by wavefield extrapolation in common 3D shot gathers for towed-streamer. 3D convolutional SRME uses cross-convolution of the recorded data either with itself or an estimate of the primary wavefield.
In practice, the recommended solution depends on the water depth of the data. For most datasets an appropriate combination of these technologies is applied to effectively attenuate multiple energy and provide multiple-free data for imaging.
Velocity Model Building
OGF’s velocity model building technology has all the tools needed to quickly build an accurate velocity model for time or depth imaging. The hyperBeam toolkit enables quick, effective velocity model building for any geological setting. hyperBeam can tomographically model build in offset and angle domain and can build not only velocity models but anisotropy and Q models as well.
The OGF model building toolkit also incorporates FWI technology, which allows us to add more detail to resolve complex velocity issues.
Accurate, reliable imaging of the subsurface requires an appropriate choice of migration algorithm. The OGF imaging suite includes a full complement of industry leading imaging algorithms. These algorithms include Kirchhoff time, Kirchhoff depth, PGS Beam, Wave Equation Migration (WEM), Reverse Time Migration (RTM), and Least-Squares Migration (LSM). All OGF migration algorithms are Q enabled.
OGF imaging offers a special high resolution processing flow that uses either newly acquired Geostreamer data or vintage conventional streamer to accurately image very small shallow structures. This workflow provides the benefits of a traditional shallow hazard survey at a fraction of the cost.
The OGF imaging team can apply the full benefits of modern processing technology to vintage dataset, including survey matching and merging. Our reprocessing workflow is suitable for both 2D and 3D data.