FairfieldNodal’s depth imaging capability is built around a proprietary and fully integrated set of tools, workflows and algorithms that are purposefully designed to take advantage of the wide azimuth illumination that node acquisition provides.  

Carefully prepared node data is given to expert teams of model builders and depth imaging geophysicists who fully understand your imaging objectives. Our earth model building incorporates:

  • Patented process for producing 3D angle gathers from sparse node geometries
  • Global tomography
    • Full azimuth (mirror or primary)
    • Accepts OVT, common offset and angle domain common image gathers (ADCIGs)
  • Anisotropic corrections

Acquisition to final image:  experts at every step

Our expertise in node technology extends beyond acquisition.  From high performance computing to highly optimized imaging algorithms our processing and research teams are committed to providing the best technical solution to complex imaging and reservoir management problems. 

Our time and depth migration algorithms include: 

  • Kirchhoff PSTM – isotropic and anisotropic
  • Kirchhoff PSDM – isotropic and anisotropic
    • Common offset
    • Offset vector tile (OVT)
  • Wave Equation (WEM) – isotropic and anisotropic
    • Output angle domain common image gathers (ADCIG)
  • Reverse time migration (RTM) –  isotropic and anisotropic
    • Model updates with ADCIGs

Mirror Migration

In deepwater ocean-bottom node (OBN) acquisition, each node records reflected energy from the subsurface more than once. Seismic energy can arrive directly at the seafloor (upgoing waves) or after a near-total internal reflection at the air-water interface (downgoing waves). With both a hydrophone and geophone in each node, these two wavefields can be processed separately, providing different illumination of the subsurface. Mirror migration images the downgoing wavefield, providing superior illumination of the shallow horizons from the perspective of the virtual node position.

Wavefield migration diagram
Wavefield migration diagram
[Left] Common receiver migration of upgoing wavefield  <br />[Right] Common receiver mirror migration of downgoing wavefield
[Left] Common receiver migration of upgoing wavefield  
[Right] Common receiver mirror migration of downgoing wavefield

Anisotropy

The development of a velocity field to optimally image seismic data with pre-stack depth migration often results in a velocity that does not tie the vertical velocity derived at a well. This is due in large part to anisotropic effects in the overburden. FairfieldNodal addresses this problem with its combination of anisotropic model building and anisotropic depth migration algorithms. Our model building includes a patented method for calibrating seismically derived velocity models with existing well information, followed by three-parameter velocity analyses that scan for v0, and the Thomsen parameters: delta and epsilon. We can use the anisotropic model to migrate using our Kirchhoff, wave-equation shot migration, and reverse-time migration algorithms.

Well Velocities1
Well Velocities2
Isotropic
Anisotropic