2024 Exploratory Surveys

During 2024, two exploratory surveys were carried out in the areas of the Allocation Plan for Offshore Renewable Energies (Plano de Afetação para as Energias Renováveis Offshore – PAER):

Seismic data acquisition during the 2024 survey onboard the R/V Mário Ruivo

Multibeam Exploratory Survey

The multibeam echosounder (MBES) exploratory survey was commissioned by IPMA to Instituto Hidrográfico (IH).

>> Surveyed PAER areas: Viana do Castelo Sul, Leixões and Figueira da Foz

>> Acquisition of first complete mosaics of MBES data – bathymetry and backscatter

Areas covered by the MBES survey

Equipment and parameters:

  • Spatial resolution of multibeam bathymetry and backscatter models:
    • 8 m for depths in 80 – 160 m range
    • 16 m for depths in 160 – 320 m range
    • 32 m for depths > 320 m

Sediment sampling

Sediment samples are used for the calibration of acoustic backscatter data.

A total of 69 sediment grab samples were collected in the three areas with a Smith McIntyre grab sampler and analysed for grain size and total organic and inorganic Carbon.

Example of data acquired by IH during the 2024 MBES exploratory survey, here shown for the Leixões area. Left: bathymetry data; Center: backscatter data; Right: white dots locate the grab sediment sample locations (background image: seabed seabed lithology from the EMODNet-Geology portal)

Seismic Exploratory Survey

The 2024 seismic exploratory survey was conducted onboard IPMA’s R/V Mário Ruivo

>> Acquisition of the first datasets of ultra-high resolution multi-channel seismic (UHRS) and sub bottom profiler (SBP)

R/V Mário Ruivo
Line plan for the 2024 Seismic Exploratory Survey

>> Surveyed PAER areas: Leixões and Figueira da Foz

>> Total 2167 km of geophysical data

>> Line spacing: 1.5 km (main lines) and 3 km (cross lines)

>> Two tie lines connecting the two areas

Equipment:

  • Multi-channel seismics (UHRS):

Marine mammals observation (MMO)

Continuous monitoring of marine mammals activity was ensured to mitigate the impact of acoustic noise on cetaceans.

  • Direct visual observation of mammal and other fauna activity
  • Passive acoustic monitoring system (PAM)
  • Compliance with the JNCC mitigation guidelines 
Triple layer sparker
Deployment operations
Seismic acquisition

+ Photo Gallery

Geomodel

A preliminary Geomodel was built from the interpretation of all datasets, and includes:

  • Main seismic packages
  • Four horizons per site
  • Geohazards (channels, faults, mass transport deposits (MTDs), fluid bearing sediments, …)

Examples of acquired data

Example of UHRS seismic data (top) and zoom to the black rectangle (bottom)
Seismic facies of channel infils in the continental slope
Detail of multichannel UHRS data showing highly resolved features in stratigraphic record; pre-Pliocene unconformity; and unconsolidated detrital sediments at the seafloor

Multichannel UHRS seismic data showing a mass transport deposit (MTD)
Multichannel UHRS seismic data showing faults in the bedrock strata
Example of sub-bottom profiler (SBP) data at different scales, showing the uppermost sediment layers

Survey partners and contractors

https://www.oarsgroup.com/

>> Coordination and MBES data acquisition and processing

>> Seismic data acquisition

>> Consulting in survey management

>> Client representatives

>> Seismic processing and interpretation (Geomodel)

>> Seismic interpretation (Geomodel)

>> Marine fauna observation