FMU sim2seis

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Why sim2seis? ​

The FMU sim2seis (simulator to seismic) workflow calculates seismic parameters and synthetic seismic based on reservoir simulation results. Typical use cases include:

  • Feasibility studies for 4D seismic
  • History matching to 4D seismic data
  • Assisting the interpretation of 4D seismic data

The following steps are typically undertaken when calculating synthetic seismic from reservoir simulation results:

  1. A field-specific petro-elastic model (PEM) is used to calculate elastic parameters in each grid cell. Static and dynamic parameters from the geomodel and simulation model serve as inputs to the PEM.
  2. Synthetic seismic cubes are generated based on the input from the two steps above and a seismic wavelet.
  3. Depth-to-time conversion is performed on the synthetic seismic cube to prepare for relative seismic inversion.
  4. Optional: relative seismic inversion is applied to the time-converted synthetic seismic cubes.
  5. Time shift estimation is conducted based on the synthetic seismic differences.
  6. Various results can then be extracted, such as:
    • attribute maps from the synthetic seismic and relative seismic inversion. The list of possible attributes can be found in xtgeo.cubes.
    • time shift change maps

sim2seis settings are read from a YAML file. The section links above discuss the parts of the YAML file that control the matching aspect of the sim2seis workflow. Lines in the configuration YAML file that are commented indicate default values, which are typically preferred, such as file names, directory names, etc.

There are two related commands that are optional within the sim2seis workflow:

  1. Observed data processing
  2. Clean-up of intermediate files

Neither of these commands is usually included when sim2seis is run from ert, but they can be in certain cases. Both have command-line interfaces, which are explained in the links above.

ERT Run ​

The steps from PEM to attribute_maps are based on results from previous steps in the sim2seisworkflow, so they must be run in a fixed sequence in ert. The minimum mandatory sequence is:

  1. PEM
  2. Seismic forward modelling
  3. Amplitude maps

If relative acoustic impedance is also included, the sequence becomes:

  1. PEM
  2. Seismic forward modelling
  3. Relative acoustic impedance
  4. Amplitude maps
  5. Relai maps

A setup file for an ert job is shown in ert configuration.