A highly biased article, but interesting to show that “spin” can be hard to detect. While TAPS has withstood earthquakes and floods, it hasn’t withstood bombing and drunks shooting at it with high-powered rifles (TAPS 400 Bullet Spill). And despite what the article says, it has developed leaks due to corrosion. Their pigging program doesn’t always work. The $400M “Strategic Reconfiguration” is moribund. And so on… Original article source is http://energy.seekingalpha.com.
Trans-Alaska oil pipeline still delivers
by Tim Bradner
27-06-07 It has withstood earthquakes and floods, whistleblowers and congressional hearings. At age 30, the trans-Alaska oil pipeline has stood the test of time. It has defied the critics in the early 1970s who predicted pipeline ruptures and massive oil spills, and displaced and decimated caribou herds.
Today the caribou are doing just fine, and so is the pipeline. The federal and state governments have reauthorized its right-of-way leases for another 30 years and Alyeska Pipeline Service, the pipeline’s operator, is in the midst of a $ 400 mm-plus pump station reconfiguration project which will allow the pipeline to operate more efficiently as North Slope oil production declines.
The pipeline has been around for a generation of Alaskans to grow up not understanding its importance to the state or the nation. North Slope oil delivered by the pipeline constitutes one-fifth of the nation’s domestic oil supply. For Alaska, the oil the pipeline delivers pays 85 % of state public services.
Alaskan 30-somethings also may not comprehend the magnitude of the pipeline construction project, nor the innovations that went into it which were unprecedented, many of them designed and implemented in the field.
Bill Howitt, a former senior manager at Alyeska, is still amazed that the construction logistics were managed as well as they were in days when computers were not so readily available, with thousands of tons of equipment and materials delivered to often-remote locations along the pipeline’s 800-mile route.
“Our spreadsheets were on our clipboards,” said Howitt, now retired and living in Oregon. The numbers are mind-numbing: 78,000 vertical support members, and 120,000 “head pipes,” devices installed to keep soils frozen at the base of the vertical support members.
There were huge design innovations during construction, and most of them have worked, some very well. One of the most important was the pipeline’s earthquake protection system, which was validated in a major way.
When a quake that measured 7.9 on the Richter scale hit the Alaska Range in November 2002, the earthquake design worked exactly as intended. The system allowed the pipe to move laterally as much as 18 feet with the intense earth movements without rupturing or even significant damage.
The support system experienced some damage and the pipeline was shut down for 66 hours to allow repairs, but no oil was spilled, according to Elden Johnson, another veteran involved in the design, construction and 30-year operation of the pipeline, who is now a senior engineering advisor to Alyeska.
The pipeline is designed to withstand an 8.0 magnitude earthquake at the Denali Fault crossing and can accommodate an 8.5 magnitude event near Valdez, Johnson said. As it happened, the earthquake came two weeks before federal and state agencies were to give their final approvals on the pipeline’s 30-year right-of-way renewals.
“This was Mother Nature’s final exam on our renewal application,” Johnson said.
The earthquake design was unique, Johnson said. Nothing like it had ever been done before, and Johnson said credit should be given to experts who developed the design for Alyeska; Lloyd Cluff, a geologist, and Nathan Newmark, an earthquake scientist at the University of Illinois, as well as Jim Maple, a structural engineer.
Another dramatic success of the pipeline’s engineering was construction of the pipeline above-ground for more than half of its length, and the design of the vertical supports and horizontal cross-members that allow the pipe to move when it needs to. Techniques like these had never been used on a pipeline but they were necessary for the pipeline to overcome the challenges of permafrost and unstable soils, conditions about which the pipeline builders knew little when they began work on the immense project in the late 1970s.
Howitt said Alaska’s own professor Hal Peyton, head of the civil engineering department at the University of Alaska Fairbanks, deserves some of the greatest credit for educating hundreds of young pipeline engineers about permafrost, himself included.
“At the time, the oil companies didn’t know anything about permafrost,” Howitt said. “Had the pipeline been built as it was originally conceived by the companies, it would have been an absolute disaster, ecologically as well as from an operational and reliability standpoint.”
The good news, however, is that Alyeska had the foresight to ask Peyton and other Alaskan engineers for help, Howitt said. Peyton went on to help Alyeska do the engineering designs needed to deal with the problem.
Howitt said the need to build the pipeline above ground for half of its length was a major factor in the huge — almost 10-fold — increase in the cost of the project, from $ 900 mm estimated in 1970 to its final cost of $ 8 bn. The pipeline was originally designed for burial along its entire route when the project was first conceived and pipe ordered in the early 1970s.
However, the above-ground design has also been a great successin helping the pipeline adjust to changes in its environment over the years, Johnson said, allowing room for movement to adjust to thermal expansions or contractions, and at settling or subsistence of soils due to the effects of global warming.
“It has taken the risk out of global warming for us. The adjustments have become routine maintenance,” Johnson said.
Some permafrost along the pipeline route is only marginally stable, particularly through the southern regions.
“Near Glennallen the soil temperatures are at 31.9 degrees Fahrenheit, so even a very small degree of heat transfer can cause shifting and settlement. But we can watch for that, and do the maintenance needed. It has given us a lot of assurance,” Johnson said. Along with the above-ground construction came technologies to help keep soils frozen, such as the heat pipes, which were innovations on their own, Johnson said.
River crossings were another huge challenge, Howitt recalled. Since there was little information on stream flows or how much flooding there might be, the pipeline builders had to go back to the basics, gathering information about weather and estimating flood-stage levels, currents and, most important, the amount of bottom-scouring that might expose or endanger a buried pipeline.
It was amazing that the engineers and scientists Alyeska hired got all this mostly right, Howitt said. There were problems in two or three areas, but these were resolved, he said.
Howitt said the basic welding program for the pipeline has proven the test of time. The trans-Alaska oil pipeline is the only pipeline that has ever had 100 % of its 105,000 “girth” welds — welds around the main pipe — checked by X-ray inspection. There has never, to date, been a failure of a mainline weld, a remarkable achievement, he said.
“This validates the underlying design and quality of the welds,” Howitt said. It also demonstrated the qualifications of the welders doing the work, many who came from other states. “They were indeed prima donnas,” Howittacknowledged, “but they knew what they were doing.”
This isn’t to say there haven’t been problems. There were, in fact, two leaks from the pipeline in 1979, two years after start-up, caused by settling of soils in permafrost areas. One was near Atigun Pass and a second was north of Thompson Pass. In one area the soil settled four feet.
“These were important lessons for us. We began an aggressive program of checking for deformations of the shape of the pipeline with survey monitoring and instrument pigs,” or devices shipped through the pipeline to check on its condition, Johnson said. If the operations of the pipeline have been relatively smooth over the years, a good bit of credit must go to the pipeline’s original design, Johnson said.
“It was built to be tough,” he said.
In terms of operations, Howitt and Johnson agreed that a big innovation for the pipeline was the first-ever use of drag reduction agent, or chemicals injected to reduce friction and allow more liquids to be pumped through the line than would have otherwise been possible. This had never been done on the scale accomplished by Alyeska on the pipeline. Without the use of DRAs the pipeline would have been capable of pumping only 1.4 mm bpd. With the chemicals, it transported as much as 2.1 mm bpd.
“The DRA saved us from having to operate two more pump stations,” Howitt recalled.
Pump Station 5 was built, but not as a full pump station, and nothing was ever built at the originally planned Pump Station 11. Fewer pumps were also installed at two other pump stations than were planned. It was expensive, however. At the peak of 2.1 mm bpd throughput, Alyeska was using 25,000 gallons of DRA per day at a cost of $ 11 per gallon, Howitt said.
The use of “smart” pigs for maintenance was another innovation with the pipeline.
“We didn’t invent the technology but we were the first to use them as aggressively as we have,” Johnson said. There have been more than 60 runs of smart pigs over 30 years, and today there are about two runs per year to check for corrosion or changes in the pipeline’s internal shape.
Corrosion has always been a concern, Johnson said, but there has never been a leak from the main pipeline due to corrosion. In 1989, Alyeska did find extensive external corrosion in a section of buried pipeline near Atigun Pass and on the Chandalar Shelf nearby. The company had made use of an improved instrument pig that used ultra-sound technology to check for changes in pipe wall thickness.
When several anomalies turned up, the company went and dug up pipe to check, and found corrosion. That led to 8.5 miles of pipe being replaced near the Atigun River and numerous “spot” digs and repairs along the Chandalar Shelf that resulting in about a third of the pipeline in the area being examined and repaired. In some cases steel sleeves were installed to structurally reinforce the pipe.
The validation of Alyeska’s pipeline integrity management program, based on the use of smart pigs, is that it has now been widely copied for use on other pipelines.
Many of its elements have been incorporated into US Department of Transportation pipeline safety regulations, so that they are now the standard for pipelines across the nation.