pipeline route selection
1. Pipeline routing
Successful pipeline routing is the key to providing a pipeline system
that optimizes material cost, construction and safety. Pipeline routing is
inevitably a compromise between opposing factors of minimum route length,
avoidance of populated areas, wet or rocky ground or mountainous regions,
reduction in major crossings, statutory requirements and obtaining permission
of landowners.
1.1 Route selection principles for onshore pipelines
a. Legislative
requirements
b. Land ownership
and compensation
c. Environmental
sensitivity
From a routing viewpoint, avoidance of sensitive areas
is generally to be avoided, but if unavoidable, reducing this length to a
minimum. This includes areas set aside as national parks and other similar
designations as these areas often have additional legislation protecting them
from development or construction.
An accepted method with which to allow routing of a
pipeline in sensitive environmental areas is agreement with concerned
environmentalists the means and manner of the reinstatement works following
construction. This often requires special areas and means of working and will
need to be identified during detail routing.
d. Habitation
Villages, towns and cities need to be avoided, and
often by a sufficient margin so as to avoid any impact in the future for
expansion.
e. Land use and type
f. Topography
Pipeline construction is easiest in flat or gently
sloping, well-drained soil. Conditions outside of this are feasible for
construction, but the severity of the slope and type of ground need to be
considered when choosing alternatives. Mountainous regions, which are often
accompanied by hard rock, cause considerable additional difficulties in
construction which is reflected in the cost, which can be up to 10 times
greater than a similar distance on the easiest sections.
g. Crossings
The number and type of potential crossings often
affect the overall routing of a pipeline onshore. In general, crossings of any
major road or river should be avoided where possible or the number of times it
crosses the same feature reduced to the minimum.
h. Safety codes and
requirements
Minimum proximity distances of the pipeline from
certain dwellings are required by certain design codes, as recognition of the
potential effect of a gas pipeline rupture for whatever reason.
i. Construction
access
j. Existing
pipelines, utilities and overhead power cables, structures, obstacles etc.
k. Shortest distance
The principal aim of most pipeline designers is to be
able to construct the pipeline in the shortest time for the lowest possible
cost. Thus, all other items being equal, the shortest route plotted between the
end points of the pipeline would be the cheapest. Apart from desert and bush /
scrub locations, this is not normally practical, however deviations from the
straight line should be held to a minimum.
1.2 Route selection requirements for offshore pipelines
a. Route length
b. Existing
pipelines, utilities and overhead power cables, platforms, structures,
obstacles etc.
c. Review of
existing survey data
d. Future developments
e. Anchoring and/or
restricted areas
f. Pipeline
crossings with third parties
g. Potential for self-burial
h. Riser locations/topside tie-ins
i. Platform
approaches
j. Expansion loop
dimensions
k. Installation
aspects
l. Protection of the
system
m. License
requirements from regulatory bodies or third parties
n. Fishing patterns
The following points may
also be raised
a. Allowable bend radii
b. Pipeline route
clearances – minimum clearance for all existing or future developments for the
prevention of potential construction vessel anchoring problems
c. Pipeline
crossings – proposed solutions if this problem is encountered
d. Sea bottom
variations
Comments
Post a Comment