Geophysical Surveys
Geophysical surveys involve measuring the physical properties of the seabed and determining the presence of any feature or change in a material composition.
This information aims to inform on the nature and variability of ground conditions on-site, to assist with future investigation works and to determine potential project engineering ground risks.
We own and operate a full spread of sub-bottom profilers, side-scan sonar and magnetometers in addition to singlebeam and multibeam echosounders and have considerable experience and expertise in the field of geophysical survey.
Advice regarding equipment selection can be given to meet the client’s requirements, taking the water depth, type and composition of the seabed at site into consideration.
Our experience includes Offshore Renewable Energy sites, Offshore Oil & Gas, Ports & Harbours, Pipeline and Cable routes and high resolution surveys for engineering developments & structures.
With geophysical data capture completed using either individual or a combination of sensors, interpretation, analysis and reporting offered as standard we are uniquely positioned to offer our clients a comprehensive report outlining the sub-strata conditions not only within the required survey area but also of the geological conditions within the survey locale.
This can be supported by a desktop geological report, incorporating supplementary seismic data, existing maps and data from offshore and onshore borehole databases and presented in scaled digital drawings that can be easily understood and used by both engineering and non-geophysical specialists.
There are a number of geophysical techniques available, each one measuring the different physical properties of the seabed, and each varying in sensitivity to different types of geological features.
Sub-strata interpretation is carried out with an array of sub-bottom profiling systems ranging from Sparker and Boomer systems to Chirp and Pinger equipment and the the variety of power output and frequency from each system ensures the chosen methodology is based on the client’s requirements and the environment being investigated.
In order to obtain a more detailed understanding of the seabed, high frequency side-scan sonar can be used to allow small objects to be imaged reliably, thereafter analysed in data-processing software to detect and classify targets of interest. Additionally, the side-scan backscatter data can be used to provide the same geomorphological analysis as is the case with the multibeam backscatter, but with improved resolution, affording a more reliable interpretation.
Magnetics are useful over large areas to aid in the analysis of the sub seabed geology as they can assist in locating changes in the sub surface geology. Additionally they can assist in detection of metallic objects sub seabed.
In line with industry practice and our own environmental commitment, we routinely provide qualified (MMO) Marine Mammal Observers from within our own staff for all sub-bottom profiling surveys.
All of the above can be brought together within an overall geological report to provide a background understanding of the area being investigated. Output deliverables include Digitised Geological Profiles, Digital Drapes, AutoCAD drawings, PDF and standard ASCII, XYZ, SEGY, XTF files and other industry standard formats.
