Geophysical servicesApplied geophysics is how we provide spatial information about geology. Ramboll performs a wide range of geophysics investigations as part of our services for a variety of different clients and markets. This includes eg site investigations for on- and offshore infrastructure projects; surveys for offshore wind farms; groundwater mapping; investigations for foundations, structures and archaeology and engineering; as well as prospecting investigations for the mining industry.
The integration of geophysical data with other investigation methods provides an enhanced understanding of the site conditions. The overall outcome is lower costs and risk reduction.
The desired depth of investigation, resolution and the geology determine which geophysical method being the most suitable. Most of the geophysical methods have the advantage that they are non-intrusive and leaving none or very few evidence from the geophysical activities in the area. At the same time geophysical methods are truly in-situ methods since the ground is not disturbed by the measurement. Therefore geophysics provides a very important tool in the investigation toolbox.
Ramboll has a very large pool of instruments operated by skilled geophysicists making it straight forward for us to choose the best method and to set the right team for the specific assignment.
Applications of geophysical methods
The application of geophysical methods within Ramboll ranges from geotechnical applications such as foundation for buildings, infrastructure site investigation surveys to offshore wind farm and environmental studies.
Infrastructure and building constructions
Geophysical investigations have become an integrated part of the geotechnical site investigation for foundations, tunnels, and highways. Ramboll has performed numerous on- and offshore geophysical investigations and has for example played a key role in understanding the geology in preparation for establishing the Fehmarn Belt Fixed Link tunnel between Denmark and Germany.
Geophysical investigations have become an integrated part of the geotechnical site investigation for foundations, tunnels, and highways. Ramboll has performed numerous on- and offshore geophysical investigations and has for example played a key role in understanding the geology in preparation for establishing the between Denmark and Germany.
Offshore wind farms and Cable route surveys
For offshore wind farms Ramboll conducts surveys for future and existing sites and turbine locations as well as planned routes for the power cable and post-installation depth of burial surveys. We also undertake analysis of both the shallow soils within foundation zones to identify geo-hazards such as shallow gas, shallow water flow and faulting. Integrated 3D geo-models combining available geophysical and geotechnical data are also among Ramboll´s core expertise.
Offshore cable tracking surveys
The offshore infrastructure develops rapidly. Long distance power lines across the seabed are being established and have to be inspected regularly as well as power lines from offshore wind farms. Ramboll has managed a number of pipe and cable tracking projects.
Mineral exploration and mining engineering
Within the field of mineral exploration it is typical to have an extensive feasibility study to evaluate whether the proposed mineral project can be mined economically. Geophysics is used to explore new targets, to delineate existing targets and for surveys related to engineering and environmental issues.
Natural resources and energy
In connection with any onshore project it is crucial to have a sufficient knowledge about subsurface geology. By using geophysics it is possible to obtain a better understanding of sediment thicknesses and bedrock quality. Ramboll has performed geophysical surveys for nuclear storage investigations, oil & gas exploration, shale gas exploration and geothermal exploration.
Water resource, environment and waste management
Geophysics has been an important and integrated part of the mapping of the groundwater reservoirs for the Nature Agency in Denmark. Ramboll has performed numerous groundwater mapping surveys in Denmark between 2000 and 2015. Especially reflection seismic, transient electromagnetic (TDEM) and resistivity (ERT) surveys have become a standard for mapping water resources.
Archaeological geophysical surveys can be performed e.g. for museums as a tool to steer excavations or when non-invasive techniques are required. However, the majority of archaeological geophysical surveys are performed prior to the commencement of any large infrastructure project it is required as standard to perform an archaeological survey in order to identify any historical artefacts. Ramboll has performed several archaeological surveys both on- and offshore.
Fields of expertise
The subsurface is comprised of materials consisting of different physical properties. Clay and limestone, for example, have different densities, acoustic velocities, elastic moduli, electrical conductivities, magnetic susceptibilities, and dielectric constants. Geophysical instruments are designed to map spatial variations in the physical properties of the Earth.
The large selection of methods and instruments allows us to carry out virtually any kind of geophysical investigation and allows us to choose the optimal method for a specific project. We use state-of-the-art equipment and perform advanced data analyses and data processing to meet the highest standards. Our services are customized to each customer’s needs and are supported by our in-house team of geologists, hydrogeologists, geophysicists, and engineers.
Ramboll offers a wide range of geophysical services:
|Seismic reflection investigations|
Ramboll has developed and used an innovative land streamer method for seismic acquisition since 1999, for which the improved working methodology has given a unique capability of acquiring data with a cost effective, fast and versatile system without compromising the data quality. Furthermore Ramboll also performs or supervise traditional reflection seismic surveys and does the processing and interpretation of the acquired data in-house.
Reflection Seismic brochure
|Seismic refraction investigations on- and offshore|
|Ramboll is using the refraction seismic methods for mapping the depth to the hard rock or basement. Beside the traditional land or onshore survey, Ramboll has a long track record of acquiring refraction seismic data offshore in water depths of up to 300 m.|
|Seismic surface waves and shear wave investigations|
|Ramboll uses a land streamer method for shear- or surface wave seismic acquisition, using a vibroseis source or an accelerated weight drop as energy source. For shear wave acquisition the vibroseis source is set up for generating shear waves. The Shear wave velocity soundings and results from the surface waves are used to calculation of the dynamic parameters of the formation for geotechnical purposes.|
|Vertical Seismic Profiling (VSP) and Crosshole Seismic|
Shear (S-wave) and P-wave velocity of the formation can be measured using a 3-component geophone and together with the density of the formation the dynamic parameters of the formation can be estimated: G – Module, Young and Poisson ratio. The VSP measurement can also be performed for time to depth correction using a Hydrophone cable lowered into the borehole. In addition to this we use cross-hole tomography for illuminating the structures and shear and pressure wave velocities in-between boreholes.
VSP - brochure
|Crosshole Sonic Logging (CSL)|
Variations in the concrete in deep foundation piles and concrete walls can be determined by using a crosshole sonic logging system (CSL). Prompted by industry demand for a method to test the structural integrity of concrete in foundation piles Ramboll has invested in a crosshole sonic logging system.
|Geophysical borehole logging|
Geophysical borehole logging or wireline well logging is performed in boreholes drilled for groundwater, oil and gas, mineral and geothermal exploration as well as part of environmental and geotechnical studies. The borehole logging is performed to obtain a detailed record of the geological layers penetrated by the borehole. Our logging programme includes temperature, flow, resistivity, natural gamma, EM-induction, deviation, caliper, acoustical- and optical televiewers, magnetic susceptibility, density, porosity and full-wave-form sonic logs.
Geophysical borehole logging – brochure
|Electrical Resistivity Tomography (ERT) (CVES or MEP), Spontaneous Potential (SP) and Induced Polarization (IP) studies|
Geo-electrical methods are based on the fact that different geological deposits have different electrical resistance. The method can be used to gain knowledge about the geology down to around 130 meters. Ramboll also does marine ERT measuring using special equipment.
ERT – brochure
|Electromagnetic methods / Slingram / DualEM|
Detailed mapping of the top soil layers (down to approximately 6 m) can be performed using an electromagnetic method that measures the apparent electric resistivity.
DualEM – brochure
|Time Domain Electromagnetic (TDEM)|
For mapping of the geology for e.g. groundwater reservoir or conductive mineral bodies, Time Domain Electromagnetic (TDEM) or (TEM) can be used. The methodology gives an overall picture of the geological structure to a depth of approximately 150 m for land based and down to app. 350 m for air based systems like SkyTEM. TEM measurements can be performed using both a land based and an air based system. The air based system is used for large survey areas.
TDEM – brochure
TDEM Saline water – brochure
SkyTEM – brochure
|Ground Penetrating Radar (GPR)|
A ground penetrating radar system can be used for a number of applications for construction or geological surveys such as: measuring pavement thickness, locating utilities, detecting voids, sinkholes, faults, UXO, underground storage tanks, cables and rebar in concrete, archaeological purposes and for geological profiling incl. estimation of depth to hard rock. Ramboll has a number of GPR systems, both 3D GPR and conventional 2D systems.
3D GPR (roads) – brochure (DK)
3D GPR (utilities) – PDF brochure (DK)
3D GPR (archaeology) – PDF brochure (DK)
For mineral exploration a ground magnetic survey could provide high resolution information about magnetic variations in the near surface geology as well as in the depth. Magnetometry is also an established method in engineering geological surveys where it can be used to map e.g. dolerite dikes.
Magnetic – brochure
High sensitivity metal detectors can be used for various applications. For locating and mapping of buried storage tanks, mapping pipes and other utilities, munition and for archaeological surveys.
Metal Detection – brochure
|Ramboll acquires stationary and mobile laser scanning on roads, railways and from boat for scanning of constructions. The marine laser scanning above the water level can be combined with multibeam for constructions under water.|
|Magnetic Resonance Sounding (MRS)|
MRS is the only non-invasive geophysical method that directly estimates water content and permeability without drilling.
MRS – brochure
|Marine geophysical investigations|
Mapping the seafloor and the subsurface is a multi-disciplinary task. The mapping is performed by a marine geophysical investigation that can consist of a variety of acquisition methods: Side Scan Sonar, Multibeam sonar, Sub Bottom Profiling, magnetometer and ultra-high resolution multichannel seismic.
Marine – Brochure
|The purpose of a cable tracking survey is to acquire data to be used for marine cable burial assessment and to provide the basis for evaluation of the installation work and to monitor the stability of the seabed.|
Project Director Geophysical investigations
Chief Project Manager Geophysical investigations
Global Service Line Leader, Water Resources Management
Head of Department Geophysics and Geohydrology
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