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…).
The advantages of resistivity imaging to dredging
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:
Applications of marine electromagnetics to MRE projects
Our systems adapted to the MRE
Our active systems are particularly well suited to MRE issues:
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.
Applications of electromagnetics to cables and pipelines
Our systems for cables and pipelines
Our active systems are particularly well suited to the problems of dredging:
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.
Applications of electromagnetics to UXO detection
Our systems for UXO detection
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:
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.
Applications of electromagnetics to Defense
Our systems adapted to Defense issues
Our active and passive systems and our expertise in electromagnetics are particularly well suited to Defense 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.
Applications of electromagnetics to port and coastal development
Our systems for port and coastal development
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.
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.
Applications of electromagnetics to Oil & Gas