Statoil uses INTViewer and its Java Plugin API to create a Velocity Scanning Workflow that helps improve seismic imaging in complex structures. 

The Challenge
Scientists at Statoil are working to improve imaging of seismic data below salt and in other hard to image structures.  One of their techniques is the iterative refinement of a velocity model by applying a constant percentage change (95%, 105%, etc.) to an initial velocity model.  The seismic data is migrated for each of the scaled velocities and the various migrated panels are scanned and picked along a horizon of interest.  Users make selections on the panels where the scaled velocity focuses the energy best A new velocity model is then derived from the process. 

Because no tool was available to perform the scanning, picking and velocity model update in one integrated workflow, Statoil contacted INT to study the feasibility of implementing this workflow within the INTViewer application. 

The INT Solution
INT was able to implement this workflow as a plug-in to INTViewer.  A wizard guides the users through the various steps of the procedure:

• Migration of the seismic dataset with the 100% velocity model and some variations (95% and 105% for example). This step is done outside INTViewer.
• Loading of the migrated datasets and the 100% velocity model.  A different color is assigned to each migrated dataset (corresponding to a specific percentage of the 100% velocity).
• Loading of a reference horizon (velocity has been perturbed only below this reference horizon).
• Picking along a horizon using the migrated panel where the event energy is better focused.  Each pick will be displayed int he color assigned to the percentage velocity.
• As the user picks, a new velocity model is calculated on the fly, by first interpolating the picks along the horizon, and then by interpolating and scaling the velocity vertically.  Different interpolation algorithms have been implemented, including bi-linear, bi-cubic, and natural neighbor.
• The user can save the new velocity and repeat the process for a deeper horizon.

The Results
A Velocity Scanning plug-in for INTViewer has been delivered to Statoil.  The new functionality was delivered as a single JAR  file (Java Archived File) that is installed simply by copying it into a dedicated folder inside the INTViewer installation.  This straightforward solution was possible because INTViewer is written in Java and uses the NetBeans Rich Client Platform to support its plug-in architecture.  Java is a cross-platform programming environment that offers a powerful object-oriented language, offering very good developer productivity and outstanding performance.  The NetBeans platform provides a reliable and flexible application architecture that makes it easy to create robust and extensible applications. 

As of this writing, Statoil is using the plug-in to process a 4,000sq meters survey, corresponding to 120GB of volume seismic data.  The viewer handles synchronized visualization of 3 to 5 of the migrated datasets, visualization of the 100% model and of the new interpolated mode with no difficulty.  Only the visible traces need to be loaded into the viewer (usually along an inline or cross-line) and the interpolated velocity is calculated on the fly. 

 

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