By VERN STEFANIC
EXPLORER
Managing Editor

Return to 4-C Story

Photos by Bob Compton
Captured Light Photography

Emerging Technology Matured in North Sea

4-C Projects Harvest Gulf Data

In 4-C operations, you have one hydrophone and three geophones per station -- one that is vertical, one that is in-line and one that is cross-line.

The two extra horizontal geophones are important because they measure the Shear volocity of each molecule in the solid earth (S, or shear, waves), while the hydrophone and vertical geophone measure P (pr primary) sound waves. See results

The Schlumberger proprietary OBC system is called the Nessie 4-C multiwave array, which debuted for the company in the North Sea in 1996, according to Jason Robinson, the company's business development manager.