Pipelines
All oil that is produced spends some time in a pipeline. A pipeline is the most
inexpensive method of transport available, however, the high initial investment demands a
long term commitment. A pipeline can begin at a wellsite (where it is usually called a
"flowline") or at a battery, and then goes through various transitions before it
reaches a refinery. The stages employed in the Lloydminster region can be identified as:
the producing well, transport to a battery (by truck or flowline), the Battery (the
cleaning and treating process), a Feeder Pipeline (such as the Husky Pipeline), and the
Major Trunklines (for example, Enbridge and Express).
The life expectancy of a well, the volume it produces, and the well’s distance
from the battery dictates whether the oil is flowlined or trucked to the battery. The
cleanliness of the oil is not an important concern unless it will compromise the flow,
however, corrosion caused by saltwater is a problem.
Oil, whether pipelined or trucked to the battery, can be more than 50% saltwater and
can include some sand. At the battery it is cleaned to less than .5% S & W (sediment
and water). Treated oil is taken from the battery’s sales tanks by a booster pump,
and transferred through a Lease Automatic Custody Transfer (LACT) station. The LACT system
monitors the cleanliness of the product and meters the transferred volume. Oil that does
not meet specifications can be sent back to the battery for further cleaning. The booster
pump also provides head pressure for the shipping pump which brings the oil up to pipeline
pressure. Condensate can be added at any place in the system before the shipping pump,
taking advantage of the lower pressures. A series of check valves prevents the higher
system pressures from pushing the oil back into batteries.
Husky Oil operates a large gathering system in the Lloydminster region which collects
oil from as far away as the Cold Lake fields in the north and Turtleford in the east. This
gathering system culminates at the Lloydminster Pipeline Terminal and from there is
distributed to the Husky refinery, the upgrader, and the pipeline to Hardisty. Husky
Synthetic Blend (HSB) produced by the Upgrader is also handled by the pipeline system. The
Lloydminster pipeline terminal has several tanks with total a capacity of 1,000,000
barrels. The three basic products stored in these tanks are: Lloyd Blend crude which is
approximately 20% diluent (condensate), Husky Synthetic Blend produced by the Upgrader,
and diluent (a term which includes condensate and closely related thinning materials).
Diluent is pipelined in from the Hardisty terminal and also is recycled from the oil
processed by the refinery and upgrader. The entire Husky pipeline system is controlled
remotely at the Lloydminster Terminal by an SCADA computer monitoring system.
Husky sends its Lloydminster output through another section of pipeline to the Hardisty
terminal which also has a 1,000,000 barrel tank capacity. Husky owns this section as well
and it consists of four lines which branch into five at Wainwright. Husky has dedicated
each of these lines to a specific purpose. One handles diluent coming from Hardisty, two
transport HSB, and one carries Lloyd Blend. The additional line from Wainwright to
Hardisty handles that areas output (Wainwright Blend).
Husky uses positive displacement screw type pumps driven by 500-1000 horsepower
electric motors, and centrifugal pumps driven by 600 or 2500 hp electric motors. The Husky
Mainline (from Lloydminster to Hardisty) can move up to 1000 m3/hr of Lloyd
Blend, 600 m3/hr of HSB, 150 m3/hr of Condensate, and 180 m3/hr
of Wainwright Blend. The system operates at licensed pressures up to 1440 psi. Production
is tanked at Husky’s Hardisty terminal before it is sent down the trunklines. The
trunkline transports all types of crude through the same pipes, however, these different
products command different prices and must not be mixed. Unlike Husky’s pipeline
where turbulence is not desired, turbulence is used to maintain separation of products in
the mainline.
Pipeline cleaning is accomplished through flushing and the use of cleaning
"pigs." A cleaning pig has cup seals which make it act like a hydraulic piston
and it is pushed along the pipe by product while scrubbers scrape the sides of the pipe.
"Pigs" cannot go through a pump and must be installed and removed between them
at special junctions in the pipeline called "pig traps".
Pipelines are closely monitored and controlled by increasingly sophisticated electronic
and computerized equipment. They move high volumes of crudes, safely and efficiently to
often distant markets.
