Statoil uses INTViewer and its Java plugin API to create a Velocity Scanning Workflow that improves seismic imaging in complex structures.
Scientists at Statoil were working to improve seismic data imaging below salt and in other hard-to-image structures. One of their techniques (an iterative refinement of a velocity model) applied a constant percentage change (95%, 105%, etc.) to an initial velocity model. The seismic data was then migrated for each of the scaled velocities and the various migrated panels were scanned and picked along a horizon of interest. Users made selections on the panels where the scaled velocity focused the energy best, and a new velocity model was then derived from the process.
Because no single integrated tool was available to perform the scanning, picking, and velocity model update, Statoil contacted INT to study the feasibility of implementing this workflow within the INTViewer application.
The INT Solution
INT implemented this workflow as a plugin 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 in the 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.
A Velocity Scanning plugin for INTViewer was delivered to Statoil as a single JAR file (Java Archived File) installed simply by copying it to 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 plugin architecture. Java is a cross-platform programming environment that offers a powerful object-oriented language, 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.
Statoil uses the plugin to process a 4,000 sq meters survey, corresponding to 120 GB of volume seismic data. The viewer successfully handles synchronized visualization between 3 to 5 of the migrated datasets, visualization of the 100% model and of the new interpolated mode. 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.
Headquartered in Norway, Statoil is an integrated technology-based international energy company primarily focused on upstream oil and gas operations. Statoil has about 30,000 employees in 40 countries.