# 3D 9C synthetic VSP data

## Overview

These 3D, 9C data sets were originally calculated to understand processing challenges experienced by the Colorado School of Mines Reservoir Characterization Project at their Postle Field study area. Four companion data sets have been created to evaluate anisotropy in the presence of statics.

- Isotropic model without near-surface complexity
- Isotropic model with near-surface complexity
- Azimuthally anisotropic model without near-surface complexity
- Azimuthally anisotropic model with near-surface complexity

The four models all have the same geologic layering at depth. The models with near-surface complexity were created by eroding a canyon system into the model without near-surface complexity and then filling the void with slow, near-surface alluvium.

The data were calculated using the finite-difference method.

## Acquisition geometry

Geometries for the 3D, 9C data are the same for all data sets. Each was recorded into 31 downhole positions at depths 1350 meters (m) to 1850 m with a spacing of 16.667 m.

Each data set contains 205 source lines with 205 source positions per line. The spacing of sources within lines is 16.667 m. The spacing of source lines is also 16.667 m. The well with receivers is approximately centered within the patch of sources.

## Vertical Seismic Profiling (VSP)

9C, vertical seismic profiling (VSP) data were recorded in the same well bore. In these data sets there are 217 receivers at depths 50 m to 1850 m with a spacing of 8.333 m.

## Utility

The uses for these data sets are many:

- Test and develop VSP processing and analysis skills
- Develop new ideas in the model laboratory
- Test existing tools and codes
- Solve the laterally-varying anisotropy problem
- Do it in the presence of statics and scattering
- Evaluate data density requirements of different methods
- Develop and test new methods for parameter estimation
- P-wave, C-wave, and S-wave analysis made possible through 9C data

## Access to the data

Data and detailed documentation can be found at http://s3.amazonaws.com/open.source.geoscience/open_data/SModels/SModels.html