North American Special - Trenchless International

HDD is the key to the
Keystone Pipeline
by Lyndsie Mewett
TransCanada is undertaking an innovative, cost-competitive way to accommodate the expected
growth in Canadian crude oil production over the next decade. The Keystone Pipeline project is unique
compared with other projects in that it combines both the construction of a new 2,219 km pipeline in
the US and the conversion of an existing 864 km existing pipeline from natural gas to oil service. HDD
is essential to preserve the stunning landscape and achieve the necessary river crossings.
“The challenge for the
Pembina River HDD is
ensuring we protect the
special features and the
natural beauty of the area
while getting the pipe in place
to deliver oil.”
north america
April 2009 - Trenchless International
The 3,456 km Keystone Pipeline is also
set to serve the interests of the United
States by providing a secure and reliable
supply of Canadian crude oil to meet
the growing demand by US refineries
and markets. TransCanada spokesperson
Cecily Dobson says that the project is
seen as an innovative and economic way
to accommodate the expected growth in
Canadian crude oil production during the
next decade.
Canada is the largest importer of crude
oil to America, supplying 2.2 MMbbl/d.
TransCanada has secured commitments
for 910,000 bbl/d over an average term
of 18 years for the Keystone Pipeline. Ms
Dobson says that this represents 83 per
cent of the system’s commercial design.
Approximately 2,219 km of new pipeline
is to be constructed in the United States.
The Canadian portion of the project
includes the construction of approximately
373 km of new pipeline and the conversion
of approximately 864 km of existing
TransCanada pipeline from natural gas to
crude oil transmission.
HDD: protecting the environment
The project crosses several large rivers,
including the Mississippi, Missouri, South
Saskatchewan and Red Deer rivers, using
horizontal drilling technology.
TransCanada spokesperson Terry
Cunha outlined the details of one HDD
The pipeline
The pipeline is set to be 76 cm
in diameter to Illinois and 91
cm from the Nebraska/Kansas
border to Cushing, Oklahoma.
The pipeline will be buried with
a minimum depth of cover of
1.2 m, depending on land use.
The estimated operating
pressure of new pipeline
sections will be 9,930 kPa. The
existing pipeline proposed
for conversion to crude oil
transportation will be operated
at its current approved
allowable operating pressure of
6,067 kPa.
drive, the Pembina River crossing, west of
Walhalla. The North Dakota State Forest
Service acquired 432 acres of Pembina
Gorge land in 1970 that now is Tetrault
Woods State Forest. In May 2006, the
Forest Service started to negotiate with
representatives of Keystone Pipeline.
The commission said TransCanada had
to use HDD to bury the pipe in some
locations, including parts of Pembina and
Sargent counties. The technique will avoid
the need to cut down trees in the Tetrault
Woods state forest, and a Sheyenne River
Valley scenic area in North Dakota's southeastern
corner.
In Pembina County, the crossing
involved setting up a drill rig on the
south side of the Pembina River. A 4 to
6 inch diameter pilot hole was drilled at
an inclined angle, 7 to 9 metres below the
surface of the ground and river.
Sections of pipe were then hooked to
the drill head and pulled on rollers through
the hole, under the river, to the other side
a distance of 1,051 metres. Bentonite
clay was used to fill the hole around the
pipeline.
The drive involved approximately 15
workers in making the hole to feed the
pipe under the Pembina Gorge.
Mr Cunha said that similar to other
HDD drives on the project, “the challenge
for the Pembina River HDD is ensuring
we protect the special features and the
natural beauty of the area while getting the
pipe in place to deliver oil.”
Stakeholder involvement at length
Not only is the Keystone Pipeline project
unique in the fact that it involves the conversion
of an existing pipeline, but the
project's length means that it is being
overseen by various provincial, state and
federal regulators in both Canada and the
United States.
Ms Dobson says that a comprehensive
stakeholder engagement program, developed
and adapted to specific stakeholder
needs according to the nature, location
and potential effects, has been implemented.
Stakeholders include landowners and
residents; community leaders; federal,
provincial and local elected representatives;
aboriginal and Native American
stakeholders; regulatory agencies; emergency
services organisations; special
interest groups; and, co-located right of
way owners.
“We recognise the importance of incorporating
public input into our project
plans,” says Ms Dobson. “We believe
that through consultation we can address
questions and concerns, and integrate
important public input into our activities.
“We share project information and
gather input throughout the planning
phase and incorporate feedback into our
project design and implementation as
appropriate,” she says.
Converting to oil
Converting the existing facilities and
constructing new facilities in Canada,
North Dakota and northern South Dakota
began in 2008, while construction of
new facilities in South Dakota, Nebraska,
Kansas, Missouri and Illinois will begin
this year.
“It is estimated that more than 5,000
individuals will have worked on the design
and construction of the Keystone project
by the time it’s been completed,” says Ms
Dobson.
Ms Dobson says that the first task of the
converting of the natural gas pipeline to
oil service was to isolate the natural gas
pipeline from the other pipeline to which it
was interconnected. Existing natural gas
in the pipeline was transferred to other
natural gas pipelines using a portable
transfer compressor.
According to Ms Dobson, the greatest
challenge of the conversion was to
separate the converted pipeline from the
other gas pipelines in a safe manner while
ensuring there was no impact to existing
shippers.
Once the pipeline has been purged of
natural gas, it will be ready for the removal
of drip tanks and tie-over assemblies.
Following the isolation of the pipeline,
an in-line inspection using a pigging tool
will be completed to ensure the integrity
Timeline
of the pipeline and that it is ready for oil
service.
Overcoming challenges
In addition to the challenge of the HDD
crossing, Ms Dobson said the weather was
also a factor to be overcome. The Keystone
project experienced some extremely wet
conditions during the 2008 construction
season. In North Dakota, it was one of
the wettest years recorded in history. Ms
Dobson said that TransCanada was forced
to extend the construction season later
into the year and postpone clean up until
2009.
Keystone Wood River Pakota – expected to be in service in 2009
Keystone Cushing – expected to be in service in 2010
Keystone Gulf Coast – expected in be in service in 2011
Keystone Steele City – expected to be in service 2012
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