TotalEnergies plans to carry out geophysical and geotechnical surveys at four planned exploration and appraisal well locations in Block 58 offshore Suriname.
The surveys will be conducted at the Profosu, Fremosoe, Marbonsoe, and Sagoewenki locations. They will be done through two consecutive survey campaigns using the same vessel and equipment. The work is aimed at determining seabed and subsurface conditions in the areas of interest. It will also help identify geological hazards that could affect future drilling.
The information was outlined in the Draft Environmental Management and Monitoring Plan for geophysical and shallow geotechnical soil investigations for Block 58. The document can be viewed on Suriname’s National Environment Authority website.
Block 58 is operated by TotalEnergies, with APA Corporation and Staatsolie as partners. The block is also home to the GranMorgu development, Suriname’s first major offshore oil project.
TotalEnergies said the planned surveys will use conventional analog geophysical equipment. This includes a multibeam echo sounder, side-scan sonar, sub-bottom profiler, magnetometer, 2D high-resolution seismic equipment, and single-channel ultra-high-resolution seismic equipment.
The program will involve a single pass for all equipment. Main survey lines will be spaced at 100-meter intervals. That spacing will be reduced to 25 meters around the planned well locations. Cross lines will be spaced at 500-meter intervals and also reduced to 25 meters near the wells.
The multibeam echo sounder and side-scan sonar will be used to map the seabed and detect objects in the water column or on the seabed. The multibeam system collects seabed depth and backscatter data, which can help identify the geological composition of the seabed and the relative consolidation of substrates and objects.
The side-scan sonar will be towed across the survey area to produce seabed images. The positioning of the equipment will be optimized and calibrated before data acquisition begins.
The sub-bottom profiler will be used to map sedimentary units beneath the ocean surface. It will evaluate shallow geological hazards within the upper 80 meters below the seabed.
A magnetometer will also be used. It is a passive instrument that measures changes in the Earth’s magnetic field. The equipment can detect cultural heritage objects such as shipwrecks and aircraft wrecks, even where they are buried beneath sediments.
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The seismic component will assess deeper subsurface conditions. Marine seismic surveys use sound generated by air guns towed behind a vessel. The sound travels through the water column and seabed, reflects off geological layers, and is recorded by hydrophones.
The ultra-high-resolution seismic component will use a single boomer or sparker as the sound source. It will be towed one meter below the surface, with a single-channel streamer containing at least eight elements.
The 2D high-resolution seismic operations will use a 160-cubic-inch array as the sound source. The array will be towed three meters below the surface. A 1,200-meter streamer with 96 receiving channels will be used.
Those operations will evaluate geological hazards within the upper 1,500 meters below the seabed. The surveys form part of preparatory work for future exploration and appraisal drilling in Block 58.
