Wednesday 12 December 2018

Saudi Aramco maps Red Sea seabed

DUBA, Saudi Arabia, November 2, 2017

Saudi Aramco has undertaken an unprecedented geological task on the Kingdom’s West Coast as it looks to first understand, and then uncover, the treasures buried beneath the waters of the Red Sea.

Almost a decade ago, Saudi Aramco made the decision to conduct the world’s largest single hydrographic survey in the Saudi Red Sea waters — an area of almost 200,000 sq km.

Prior 2-D seismic data acquisition had revealed positive signs for the presence of hydrocarbons in geological traps. Just like the Eastern Province in the early 1940s, the Red Sea was frontier territory — unexplored. Its development would be a catalyst to spur growth and industry in the Western Region.

A large-scale hydrographic survey was required to fully understand the seafloor conditions. The hydrographic survey with its close grid analysis would help support all oil field operations, including rig movements, laying of pipelines, oil field facilities, and the routes for supply vessels.

“We got a good understanding, but lacked the topography of the seabed,” noted Saleh A Al-Maghlouth, manager of the Exploration Operations Department. “So we undertook this groundbreaking hydrographic survey to help us better understand the structures and where to drill.”

“The major concerns were the time constraints and vessel safety,” observed Richard G. Moffitt, Exploration Survey Unit consultant. “These were hazardous, shallow areas previously uncharted. In fact, there were old navigation charts in existence, but from several decades ago and at low resolution — insufficient for present-day vessel navigation for exploration projects. Historically, there were many more shipwrecks in the Red Sea than there were navigation charts.”

Conventional technology at the time utilized echo sounding as a means to map underwater topography, but this would have taken many years to complete. So instead, Saudi Aramco put at its disposal the latest technology available to get the job done.

What followed were 848 days of survey operations. Five specially equipped ships would spend a combined total of 2,823 vessel days using a multi-beam echo sounder to collect data for water depths between 5 meters and 2,400 metres. This technology was supported by three aircraft using Airborne LiDAR Bathymetry systems for water depths between 0 m and 40 metres, with a combined total of 1,260 survey flights completed.

The results were a new high resolution merged bathymetry grid allowing the mapping of complex geological features, including volcanoes on the seabed.

The data was encouraging for Saudi Aramco. The company was now able to move offshore rigs around and initial exploration could begin, a statement said.

Previous 2-D seismic data had been compromised in certain sections due to the unpredictable seabed topography of the Red Sea. If plausible, a 3-D seismic survey would deliver more definitive and detailed data, and combined with the hydrographic survey, it would yield immensely useful information with a high degree of certainty. – TradeArabia News Service

Tags: aramco | Red Sea | mapping |

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