Presurvey modeling is used to optimize survey geometry to meet a given objective before the data is acquired. In post-survey modeling, the starting model is updated iteratively by comparing the final processed arrival times and VSP data with the model. As the model is updated to best match what is being observed in the VSP seismic data, important structural and rock property information is revealed, such
as accurate positioning of faults, salt boundaries, and formation velocities.

Situation

• A deviated well to run sub-horizontally within a reservoir

• Poorly defined surface seismic data with 100m lateral and 50m vertical errors

• A requirement to penetrate the fault at a certain location within the reservoir

Objectives

• Run intermediate Vertical Seismic Profile (VSP), then perform on-site processing within 6 hours

• Match real results to synthetic modeling, and adjust model

Solution/Benefits

• Provided high resolution seismic information during drilling of the well

• Customer able to quickly adjust well trajectory and enter target zone at desired point of entry with lower risk of uncertainty