Feb. 9 saw a landmark event in the history of the trans-Alaska oil pipeline, when pipeline operator Alyeska Pipeline Service Co. applied the on switch to the new electrical pump system at pump station 9, south of Delta Junction.
A train of three new centrifugal pumps, each driven by a purpose-built 6,500-horsepower electric motor powered by electricity from the local electric utility, started pushing oil up the pipeline gradient over the mountains towards the marine oil terminal at Valdez. Initially the operators alternated pipeline oil flow between the new pumps and the old turbine powered pump system that had been in operation since the pipeline started up in 1977. Then, once people had verified that the new equipment was functioning correctly, the electric pumps started continuous operation. The equipment has now entered a 30 to 45-day period of operational “run in” testing, before Alyeska turns its attention to a similar switchover at pump station 3.
The old pumps at pump station 9 will remain available until the summer, in case a problem arises with the new systems.
“Our focus has been on the safe, quality startup of pump station 9,” said Kevin Hostler, Alyeska president and CEO. “We will learn from this as we move our resources to pump station 3. While this is an exciting time for us, there is still work to get done on this project.”
Strategic reconfigurationThe new pumping arrangements form part of what Alyeska terms “strategic reconfiguration,” a massive upgrade of the pipeline system to state-of-the art technology.
Under the strategic reconfiguration project, Alyeska is installing identical electrically powered pumping systems at pump stations 1, 3, 4 and 9. But, whereas pump station 9 obtains power from the local electric utility, pump stations 3 and 4 will each use two new gas turbine generators to power the pump motors; pump station 1 will obtain electrical power from the Prudhoe Bay power grid, but will also have a single gas turbine generator.
Pump station 1 is at the northern end of the pipeline at Prudhoe Bay, and pump stations 3 and 4 push oil through the pipeline up the northern side of the Brooks Range.
Pump station 5, at the bottom of the gradient on the south side of the Brooks Range, will continue to operate as a relief station, without pumping capabilities. However, Alyeska expects to mothball pump station 7 north of Fairbanks (all of the remaining five originally operating pump stations along the pipeline were mothballed several years ago in response to declining oil throughput).
On Feb. 21 Alyeska’s Pipeline Vice President Jim Johnson and Oil Movements Vice President Michael Joynor talked to Petroleum News about the benefits that Alyeska expects to gain as each of the upgraded pump stations converts to the new technology and about the current status of the strategic reconfiguration project.
ScalabilityJoynor explained that a key benefit of the new pump technology is scalability of the pumping capacity to varying pipeline throughput. That scalability comes from two aspects of the system: the ability of the electric motor variable frequency drives to vary the motor power output, and the potential to switch individual pumps in or out of operation. In contrast, the old turbine-powered pumps tend to vibrate at low power settings and have an optimum operating speed.
“The big benefit is we can run a single electric motor up to a certain flow rate. Then we bring on a second unit that takes us up to the next flow. Then a third unit if you want to go the maximum flow,” Joynor said. “… You can run (the motors) at virtually any speed you like, which gives you that maximum flexibility.”
Joynor said that after strategic configuration has been completed, Alyeska will be able to vary pipeline throughput anywhere from 200,000 barrels per day to 1.1 million bpd of crude oil.
But in the event of a major new oil find on the North Slope, Alyeska could ramp up pipeline daily throughput beyond 1.1 million barrels, Johnson said. The new pump station layouts allow for increasing the pumping power by slotting additional pumps alongside the three pumps of the standard pump station design. But achieving a maximum possible pipeline throughput of 2 million bpd would also require the equipping and re-activation of mothballed pump stations. That re-activation could be done within the lead time required to start up a new oil field, Joynor said.
Also, with the use of electric pumps, the use of modern gas turbines, the phasing out of the old turbine pumps and the phasing out of other old turbines used for electricity generation, the pipeline system will in the future generate significantly reduced emissions, Johnson said.
Efficient control and maintenanceAlthough the new pumping systems at the pump stations are perhaps the most visible aspect of the strategic reconfiguration, a complete upgrade of the pipeline control and monitoring systems to state-of-the-art digital technology also forms a critical component of bringing the pipeline system into the 21st century.
The upgrade involves the replacement of legacy 1970s era technology, Joynor said. In particular, the new systems involve deploying digital control and safety protection units to the field facilities, rather than having the control technology based at a central location. And that field distribution of the control technology will reduce the dependency of the control systems on long-distance communications.
“The person who is operating (a facility) has a complete picture of what is going on, but the protection is right there … at the facility or location,” Joynor said. “By having that protection at the facility, the facility is not dependent on the remote (central) location to provide the protection.”
Instead of people walking around the facilities every day to take operational data readings, the new systems can automatically read data and store that data in a central computer archive. That automation will increase the data points available from each pump system, for example, from about 12 to about 120, Johnson said. And the data will be collected every few seconds, Joynor said.
That mass of detailed information will enable operational fine tuning in a manner that has not been possible before, Joynor said.
Maintenance will be pro-activeAnd the information collected will also enable improved maintenance efficiency. In particular, the easy availability of data will enable Alyeska to move from maintenance based on the regular calendar-based scheduling of maintenance tasks to the performance of maintenance tasks when the condition of the equipment warrants attention. That approach will focus attention on essential maintenance and enable pro-active anticipation of equipment problems.
“A rotating equipment engineer or a maintenance technician can then retrieve that information and put in a trend.” Joynor said. “He’s able to do that from a desktop, rather than collating a bunch of handwritten readings, day-to-day data that had been collected by a human.”
In addition, the ability of everyone to access and easily display the same data will enable improved communications between operations and maintenance staff.
“The screen displays that the Operations Control Center uses are exactly the same as the displays that are available at a pump station,” Joynor said. “So when a maintenance engineer is at a facility looking at something and talking to OCC, there’s no miscommunication. They can see identically what the OCC is seeing.”
Remote operation and monitoring of the pump stations, coupled with a regional, pipeline-wide approach to more efficient pipeline maintenance, will enable a reduction in the numbers of people required on site at the pump stations, and some reductions in Alyeska office staffing, Alyeska spokesman Mike Heatwole said. Alyeska estimates that about 350 jobs will be impacted, about equally split between Alyeska staff and contractors. And those staffing reductions will all translate to a reduction in pipeline operating costs.
Alyeska is also moving to a regional approach to oil spill response, rather than basing individual teams of responders at individual pump stations. But Heatwole emphasized that staff reductions will not compromise Alyeska’s ability to deal with a pipeline oil spill — the total number of responders available to respond to an oil spill will not be reduced, he said.
Miles of cablingThe installation of large numbers of control and monitoring devices at the pump stations involves the laying of miles of electrical cabling. Johnson compared the wiring requirements of a modern pump station with the wiring required in a modern car. The introduction of sensors and computer technology has probably increased the amount of wiring in a car fourfold in the past few decades, he said.
Pump station 9 has about 2,000 new devices, requiring nearly 350,000 feet of new cabling, Johnson said. Pump stations 3 and 4 each require nearly 4,000 new devices and more than 400,000 feet of cabling.
“We’re adding devices, but at the same time we’re reducing infrastructure from the standpoint of facilities, buildings and structures,” Johnson said.
And Joynor commented that the introduction of redundant, duplicate equipment to ensure system reliability has also increased the need for cabling.
“Where we used to have one transmitter, we may now have two installed, so if we lose one, the other one’s there automatically,” Joynor said.
The pumping systems also include a level of redundancy and emergency backup. For example, pump stations 3 and 4 have two turbine generators each, although they only need one. And diesel generators would provide an emergency power, in the event of a power failure, Johnson said.
Phased approachSo, given that pump station 9 is now in operation, what is the status of the strategic configuration project and what are the next steps?
The original project plan envisaged installing and testing all of the new equipment and then switching on the whole new system once everything was ready.
“At one point we were working all facilities at the same time, to have completion of all of them at approximately the same time,” Johnson said. “We shifted from that to what I’ll call a phased approach.”
In the phased approach each pump station is switching over in turn, with the lessons learned from one pump station startup feeding through to the planning of the next startup. Pump station 9 has switched over first, to be followed by pump station 3, then 4 and then 1.
Alyeska viewed this type of approach as an effective way of dealing with any problems that would arise in a project of the scale of strategic reconfiguration, Johnson said.
So far, all of the new facility modules and associated pipe work have been installed at all of the pump stations, Johnson said. Pump station 3 is 80 percent mechanically complete but installation of cabling has only just started at pump station 1. Once all the equipment and cabling are in place at a pump station, that pump station will go through a standard procedure of functional check out, commissioning, start up and run in, with oversight at all stages by the Joint Pipeline Office and other government agencies.
“It’s all very orchestrated, with procedures and plans,” Johnson said.
The pipeline-wide digital communications system — using both microwave and fiber optic networks — that supports the new pipeline control and monitoring system is already operational. However, Alyeska is relocating the pipeline operations control center from Valdez to a building in Anchorage in 2007.
“That project is just now under way,” Joynor said.
The company is also establishing a backup control center about an hour’s drive from Anchorage, he said.
Alyeska does not have a specific timetable for the remaining pump station work.
“We’ll take our time and do it right, and do it to our specifications,” Alyeska spokesman Curtis Thomas told Petroleum News Feb. 14.