Viridien, TGS complete OBN survey in ‘mature region’ of North Sea

Joint venture partners Viridien, previously known as CGG, and TGS have completed the multi-client Sleipner ocean bottom node (OBN) survey, as well as delivered the final processed data expected to be valuable to explorers operating in the area for years to come.

The survey, the second of two dense multi-client OBN surveys acquired in the North Sea in 2023, covers 1,201 square kilometers in a mature region of the North Sea that includes the Sleipner East, Sleipner West, Gina Krog, Volve and Utgard fields, along with surrounding near-field exploration acreage – offering potential tiebacks to existing infrastructure.

The work included three node-handling vessels, three triple-source vessels and additional support vessels and was performed between June and September 2023, recording approximately 2.8 million shot points into a total of 80,769 node positions.

Viridien said it had applied its advanced imaging technology, including its latest OBN processing techniques and time-lag full-waveform inversion (TL-FWI), to capture subsurface detail at all depths. The imaged data is said to show substantial improvement in resolution and structural clarity over previous datasets, offering crucial insights into the region’s complex geology and reservoirs.

The Sleipner OBN project is supported by industry funding.

In an announcement published on December 10, Viridien also reported the completion of seismic imaging for the Selat Melaka multi-client 2D seismic program, covering the offshore area of the Langkasuka Basin, Malaysia.

The company noted that the newly available final seismic dataset indicates the presence of a previously unseen Pre-Tertiary fold and thrust belt, extending offshore across the unexplored area.

Dechun Lin, EVP of Earth Data at Viridien, said: “We are delighted to have successfully completed our first multi-client project offshore Malaysia, that leverages over 40 years of experience processing seismic data from one of the country’s major basins. We are confident that this ultramodern data set will support the efforts of Malaysia Petroleum Management, PETRONAS in promoting open acreages in Selat Melaka and spur exploration in this frontier area located near a number of proven large discoveries.”

To remind, Viridien, TGS and Aquila Holdings, under its subsidiary Axxis Multi-client, announced on November 4 the completion of the Utsira OBN reprocessing project.

Marked as the largest OBN survey on the Norwegian Continental Shelf (NCS), the Utsira project required the deployment of over 144,000 nodes and over 5.5 million shots, covering an area of 2,077 square kilometers in a mature part of the North Sea. The survey was acquired in 2018 and 2019, with the initial processing results delivered in 2020.