1. Schlumberger Limited

2. Halliburton Energy Services Inc.

3. Soci?t? G?n?rale de Surveillance SA

4. Geotech Ltd.

5. Terraquest Ltd.

6. Phoenix International Holdings Inc.

7. Geophysics Limited.

8. Quantec Geoscience Limited

9. Exploration Instruments LLC

10. Siemens AG

11. TGS-NOPEC Geophysical Company ASA

12. Abitibi Geophysics Ltd.