DREDGING

MARINE RENEWABLE ENERGY

PIPELINES & CABLES

DEFENSE

PORT AND COASTAL DEVELOPMENT

oil & gas

THE DREDGING SECTOR

DREDGING PROBLEMATICS

Marine Dredging requires a good knowledge of the nature of the marine subsurface in order to identify suitable geology, particularly the presence of sand in suitable areas and avoid rocks or potentially dangerous buried objects (UXO…).

  • Resistivity gives very useful information to built soil models, independently or together with other data (seismics, geotechnics), even in very shallow waters. For example, being sensitive to porosity, resistivity can give a direct information on the dredgeability of materials.
  • Locating sand and distinguish it from rocky areas to optimize the survey time and the quantity of sand located. 
  • Facilitating the dredging design by identifying potential boulders and superficial rocks.
  • Securing the dredging site with the detection of buried objects (UXO or debris, cables, etc.).

Our active systems are particularly well suited to the problems of dredging:

THE Renewable Energy SECTOR

PROBLEMATICS OF MARINE RENEWABLE ENERGIES (MRE)

The rapid development of marine renewable energies in Europe over the last years has created a considerable need for knowledge of the marine subsurface off the European coasts. The development of an offshore windfarm requires a control of the risks related to the type of the encountered geology or buried objects (obstructions, UXO, liquefaction or karstification phenomena…). Also, electromagnetics measurements provide precious information on the possible impact of power generators on the environment. The main issues related to the study of the subsurface for MRE are therefore:

  • Reducing the geolocial risks of the projects regarding the subsurface conditions (nature, geometry, heterogeneity) and mechanical properties, in order to position the infrastructures, to properly design the foundations, and design cable routes and groundings.
  • Securing the site by detecting obstructions and buried objects (UXO…) ;
  • Providing electromagnetic measurements  to assess the impact on the environment.

  • Facilitating the decisions regarding the locations of the infrastructures by providing geophysical information (nature, heterogeneity). 
  • Guiding the geotechnical campaign by optimising borehole locations and requirements. 
  • Securing the sites by detecting UXOs, ferrous and non ferrous.
  • Locating obstructions (boulders, rocks, buried wrecks...)
  • Once built, assessing the impact of MRE structures on the environment by measuring the emitted electromagnetic fields.

Our active systems are particularly well suited to MRE issues:

THE PIPELINES & CABLES SECTOR

PROBLEMATICS OF CABLES AND PIPELINES

The laying of submarine telecommunication cables, energy transmission cables (MRE) or pipelines requires a good knowledge of the nature of the marine subsurface in order to lay them in favourable areas and avoid potentially dangerous rocks or buried objects (UXO, etc.).

During the operation phase, the cables are likely to move or become unprotected under the effect of gradual or sudden sand movements. It is then necessary to monitor their position for verification and maintenance.

  • Provide key geophysical information for cable route and grounding, even in very shallow waters. Resistivity providing direct information about dredgeability and rippability of the materials.
  • Facilitating the laying operations by providing geophyical imaging identifying potential obstructions and  geohazards(surface rocks, wrecks, etc.)
  • Securing the cable or pipeline installation site with prior UXO detection
  • Monitoring cables and pipelines during their operational phase
  • Guiding the geotechnical campaign (in-situ tests, drilling, coring)
  • Once built, studying the impact of the power cables on the environment by measuring electromagnetic fields

Our active systems are particularly well suited to the problems of dredging:

  • The MAPPEM system for locating cables and pipelines or carrying out the preliminary geological study for their burial
  • The MAPPEM-S system for the same purposes, in very shallow waters
  • The MAPPEM-3D system for cable and pipeline detection
  • The PASSEM system for the study of their electromagnetic signature by passive measurement
  • The STATEM system for the study of their electromagnetic signature by passive measurement

THE UXO SECTOR

PROBLEMATICS OF UNEXPLODED ORDNANCE DETECTION

Whether for port and coastal development, windfarm installation or any other offshore engineering project, a critical step in site investigation is the derisking phase. UXOs left over from the Second World War are unfortunately abundant in the English Channel and North Sea. It is therefore necessary to detect them before any work on the seabed. Moreover, some of these mines are made of aluminium (for example the LMB mines) and are almost impossible to detect with conventional magnetic or acoustic techniques.

  • Localizing all buried objects that may be an UXO, including non- ferrous LMB aluminium mines/
  • Securing coastal work sites, whatever the field (MRE, port development...)

Mappem Geophysics has developed specific object detection systems that are sensitive to ferrous and non-ferrous objects (aluminium mines or LMB mines). Our active systems are therefore particularly well suited to the UXO detection:

THE DEFENSE SECTOR

Working for the Defense industry requires innovative and state-of-the-art technologies. This sector is extremely challenging mainly related to the complexity of the marine environment and the high requirements of the sector. From corrosion and cathodic protection to vessels discretion, MAPPEM is working with the state agencies and companies to provide new tools and instruments.

  • Electromagnetic fields measurements, marine electromagnetics expertise.
  • Autonomous seafloor and water colummn instrumentation.
  • Detection and localisation of buried objects (MMCM)
  • R&D projects.

Our active and passive systems and our expertise in electromagnetics are particularly well suited to Defense issues:

  • The MAPPEM system for the detection of UXO and obstructions
  • The STATEM system for electromagnetic meaurements 
  • Our unique sensors and our electromagnetic know-how and expertise, which allow us to develop and carry out effective electromagnetic solutions.
      •  

New industrial projects at sea

PORT AND COASTAL DEVELOPMENT ISSUES

In civil engineering for port and coastal development, a complete understanding of the geology of the marine subsurface is necessary to assess its influence on the detailed design of infrastructure, and thus successfully complete each phase of a new port or coastal project (design, construction, operation).

The first step should be the securing of the site (UXO, potential obstructions) prior to the works, then the second is a detailed imaging of the nature of the subsoil on the depth of influence for the planned structures.

Port development also involves the recovery of debris that accumulate on the seabed over time, and regular monitoring of the infrastructures in place.

All of these issues can be addressed with electromagnetic imaging of the resistivity.

  • Resistivity imaging to assess the geology and optimize geotechnical studies
  • Securing construction sites of port or coastal infrastructure (polder, MRE...) by prior detection of obstructions (UXO, debris...)
  • Control of infrastructures in use (cables...)

Our active systems are particularly well suited to port and coastal development issues:

THE GEOTHERMAL SECTOR

PROBLEMATICS OF THE GEOTHERMAL ENERGY

Geothermal energy is a non intermitent renewable energy . High temperature geothermal reservoirs are mainly found in volcanic contexts. A lot of these area are in coastal areas or in border of lakes all over the world. High temperature geothermal sources can be used to develop a sustainable decarbonized source of electricity. This is particularly important for islands or remote areas.

The development of such project requires a good knowledge of the temperatures distribution in the soil. This challenge can be adressed by imaging the resistivity in the area. The main method used for this is Magnetellurics (MT). 

Magnetotellurics (MT) are widely used because this technique allows to image the the subsurface from a few tens of metres to several kilometres deep and does not require an active source.

However, in coastal areas, land MT and other methods are not sufficient and an extension of measurements at sea is necessary. MAPPEM Geophysics and its partners IMAGIR are developing new instruments and methods to overcome the challenges to image the resistivity from the sea to the shore.

THE OIL & GAS and DEEP SEA SECTOR

A good knowledge of the subseabed is necessary to ensure the safe and sustainable location of infrastructures and platforms. The routing of hydrocarbons must also be carried out in such a way that it guarantees a good longevity of the pipelines and a follow-up of their position in spite of the possible displacements and modifications of the superficial sedimentary layers under the action of currents and other events. These issues can addressed by resistivity imaging, which is capable of both describing the geology prior to the positioning of platforms and pipelines, and monitoring the pipelines during the well operation phase. 

  • Imaging the geology prior to infrastructure, cable and pipeline installations
  • Pipeline monitoring during the well operation phase

Our active systems are particularly well suited to the Oil & Gas industry: