Fugro Airborne Surveys conducted a helicopter electromagnetic survey along a 130km prospective pipeline corridor to map ground conditions and aid in pipeline planning. The survey took two days and produced maps with 10m resolution showing the depth to bedrock and extent of overburden, which helps determine construction methods and reduce costs. The results identified shallow bedrock requiring blasting and deeper soils that could be trenched. A cross-section map provided additional depth information along the central flight line to aid in planning.

1. Pipeline Planning
Shallow
overburden
Ridge
Deep overburden
Bedrock outcrop
2 km
Depth (m)
5
1
2
12
3
7
9

2. Pipeline Planning
FUGRO AIRBORNE SURVEYS
Ottawa
2060 Walkley Road
Ontario, Canada K1G 3P5
Phone
Fax
Email
:1-613-731-9575
:1-613-731-0453
:postmaster@geoterrex.ca
:1-905-812-0212
:1-905-812-1504
:dighem@dighem.com
Toronto
2270 Argentia Road, Unit 2
Mississauga, Ontario, Canada L5N 6A6
Phone
Fax
Email
Fugro Airborne Surveys is a member of the Fugro Group, with offices throughout the world.
0
10m
Pipe
Depth
1 km
Overburden
Bedrock
N
Helicopter EM surveys have been borderline between soils, which
used to map apparentconductivity 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 mathematically
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 conditions 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 planning risk geological cross-section, shown
considerably. on this page. This section is
V
A 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 gaining land access and
complete, providing a map of permission for drilling. The survey
apparent conductivity with a also served as a check for buried,
resolution of approximately 10m. unknown power lines 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 define a single conditions in which pipeline
apparent conductivity value as the corrosion isaccelerated.