ASKER, NORWAY (12 April 2017) - The 2017 annual general meeting of TGS-NOPEC Geophysical Company ASA ("TGS" or the "Company") will be held on 9 May 2017 at the offices of Schjødt law firm at Ruseløkkveien 16, in Oslo at 17:00 CET.

Registration of attendees will begin at 16:30 CET.

The notice for the annual general meeting is attached hereto (English and Norwegian), together with relevant appendices. The notice will be sent to all registered shareholders per 12 April 2017.

To register your attendance, send proxy or to cast your vote electronically in advance through VPS Investor Services, please use the electronic link here and available on www.tgs.com. The pin code and reference number, which are sent out with the notice, will be needed. Kindly note that shareholders that have received the notice electronically will not receive and do not need a pin code or reference number, but must submit their notice of attendance, proxy or advance votes through their online investor account services (investortjenester).

Online registration will open on 12 April 2017 at 14:00 CET.