EarthModel™ creates 3D models from well log data. These models are used within the Jason Geoscience Workbench® (JGW) to provide the low frequency component for trace-based techniques, provide a starting point for model-based techniques and provide velocity models for time-depth conversion using VelMod™, among other things.

EarthModel has two main components, a Model Builder where the parameters of the model are set and QC output can be inspected, and a Model Generator, which uses the parametric model to output actual model files for use in other programs.

Model Builder

In order to properly interpolate well log data in 3D, a suitable geologic framework must be established. In EarthModel, the horizons and faults from a seismic interpretation are used as a starting point. However, horizons obtained from seismic interpretations are rarely tied to the well data in enough detail to be conducive to model building.

The EarthModel 'solid modeling' interpolates and extrapolates the interpretation based on user-defined limits, completing the interpretation so it exists at each trace location within all appropriate fault blocks. The horizons are properly sealed against faults, unconformities, or other truncations.

The user constructs a 'framework table' that describes the layering and deposition of the model. The table is built fault block by fault block, and from deepest to shallowest events. The table also specifies layer stratigraphy, and special events, such as reefs and channels can also be specified.

This model then becomes a layer-based framework within which wells can be placed and interpolated. The layer-based stratigraphic framework is used in many places in the Workbench:

Mapping wells to traces for Wavelet Estimation.
Creating stratigraphically correct attribute extractions in the stratigraphic slicer.
Interpolation and variogram mapping in StatMod™.

Model Generator

Once the wells have been placed and an interpolation scheme selected, wells can be propagated throughout the 3D model. Models can be generated at any time from any available well log curves.

Synthetics and Residuals

EarthModel is a powerful 3D forward-modeling tool. A wavelet can be used to to make 3D synthetic seismic data from the 3D impedance model in time.

Once the synthetics are generated, they can be compared to the seismic to see how closely the interpolation of well logs agrees with the original seismic data.

Model Interpolator

Using the layer-based stratigraphic framework, EarthModel can take any trace data set and interpolate it to a denser grid. EarthModel can also interpolate any model from one grid onto another grid, which is very useful for translating lithologic data from the seismic grid to an engineering grid for reservoir simulation.