geotechnical mapping with airborne em
TRANSCRIPT
Pipeline Planning
Shallowoverburden
Ridge
Deep overburden
Bedrock outcrop
2 km
Depth (m)
5
1
2
12
3
7
9
Pipeline Planning
FUGRO AIRBORNE SURVEYSOttawa2060 Walkley RoadOntario, Canada K1G 3P5PhoneFaxEmail
:1-613-731-9575:1-613-731-0453:[email protected]
:1-905-812-0212:1-905-812-1504:[email protected]
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Fugro Airborne Surveys is a member of the Fugro Group, with offices throughout the world.
0
10m
PipeDepth
1 km
Overburden
BedrockN
Helicopter EM surveys have been borderline between soils, which used to map apparent conductivity could be trenched, and rock which as an aid to characterizing ground would have to be blasted. The conditions in advance of pipeline data can be mathematical ly construction. The cost of pipeline inverted to produce maps of the construction is strongly dependent depth to bedrock, as shown on the on the ground condi t ions front. en co un te re d, an d ac cu ra te The calculated depth to bedrock prediction of these conditions can can also be presented as a reduce the p lann ing r i sk geological cross-section, shown considerably. on this page. This section is
VA DIGHEM conductivity survey derived from the depth information was used to map ground along the central flight line(s) of the conditions along approximately map shown on the front. 130km of prospective pipeline The airborne EM survey reduced corridor, 400m in width. The the time and cost associated with survey took about two days to ga in ing l and access and complete, providing a map of permission for drilling. The survey apparent conductiv ity with a also served as a check for buried, resolution of approximately 10m. unknown power l ines and The results are interpreted to pipelines. Airborne EM surveys determine the extent of shallow have also been used to map bedrock (which would require ground conductivity after the blasting) and deeper overburden pipelines have been constructed which could be trenched to the to detect areas of high ground depth necessary for the pipeline. conductivity due to clays or saline Over much of the survey area it is soils. These soils can create possible to defi ne a single conditions in which pipeline apparent conductivity value as the corrosion is accelerated.