Rising to meet any challenge, Allerion Oilfield Services cleans and maintains aboveground storage tanks with an eye to extracting usable oil

From the outside, aboveground oil storage tanks (ASTs) look pretty much alike. On the inside, they represent unique cleaning and maintenance challenges.

Allerion Oilfield Services has specialized in tank maintenance since the 1980s and has provided customized sludge removal solutions for ASTs for about 20 years. The company has its head office in Guelph, Ontario, Canada, about an hour’s drive west of Toronto and serves the entire country from two operations centers, one in Corunna, Ontario, in the heart of the Sarnia petrochemical district, and another in Edmonton, Alberta, which opened two years ago.

From those two bases, the company covers an area extending from British Columbia to Newfoundland. In addition to cleaning and maintenance of crude and heavy oil ASTs, Allerion also offers tank coating and lining services and API 653 inspections.

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AST maintenance customers are split evenly between pipeline companies, such as Enbridge, which transports the oil, and refiners, such as Irving Oil, which stockpile it at the other end.

Jeff Heath has been involved with AST maintenance and servicing since 1985 and has served as the president and CEO of Allerion since 2007. He represents the third generation of Heaths to head up the company.

Growth has been dynamic as Allerion takes on more work during an oil production upswing. The company’s revenues doubled between 2007 and 2010. The support contractor divides its efforts between AST service, representing about 60 percent of business volume, and sales of mixing devices, sold through Mixer Technologies, an affiliated company.



Allerion has only a few competitors in the field. “Expertise is the biggest barrier to entry,” says Heath. “You need to build up a core of workers who demonstrate the specialized mechanical ability and conscientious attention to detail.”

The company’s 40 employees aren’t necessarily tied to any particular office. About 30 are stationed in Ontario, and 10 in Alberta. Workers are assigned to contracts as needed, with tools and equipment following closely by truck.

A fleet of 20 General Motors trucks keeps equipment moving. Although the equipment array depends on the project, a typical kit includes centrifugal pumps, hydraulic power packs, hoses and valves. The company uses Godwin pumps (Xylem, Dewatering Solutions) ranging up to 550 hp and capable of moving 2,600 gpm.

The conditions of the tanks vary widely. As carbon molecules in suspension lengthen into longer chains, they attract other molecules, fall out of suspension, thicken, harden and build up on the tank floor. The sludge can include wax, heavy oil sediment, sand, scale, asphaltenes and other inorganics.

“That buildup can affect equipment, turn into an operational issue, or render the tank inoperable,” says Heath. “In some cases the tank can have 60 percent of its volume taken up by sludge. This is a 40-foot-tall tank with a typical diameter of 140 to 180 feet, filled with up to 17 feet of sludge. The consistency of the sludge can range anywhere from Silly Putty to really thick mud that you would almost need a jackhammer to break through. Some of the worst cleaning jobs can cost almost as much as the capital investment in the tank.”

Traditionally, crude oil sludge was removed from tanks and disposed of using the services of a waste disposal contractor. The sludge was vacuumed from the tanks, then treated chemically, incinerated or land farmed. Disposal costs were based on waste volume, providing little incentive for contractors to reduce the amount of waste removed from the tanks.



Allerion aims to remove as much usable oil from the sludge as possible, reducing its overall volume and returning revenue to the client. How much hydrocarbon can be salvaged and the methods used to process it depend on the makeup of the sludge.

“We begin by taking a sludge sample and sending it to the lab,” says Heath. “Depending on the hydrocarbon content, the simplest approach may be to remove it with a hydraulic scoop, dilute it and shuttle some of it into another tank for reuse, then treat the unusable portion and dispose of it.”

Tougher sludges contain a significant amount of inorganics and tank scale. These are typically piped through centrifuges to separate solids from liquids and oil from water. The company owns several of the devices, but also sources them from local waste management contractors.

Excessively high sludge levels in ASTs can even prevent the removal of manway covers, and can also interfere with the lowering of the tank’s interior floating roof. For these situations, the company does prep work using its ATC Lance, an articulating lance inserted into the tank to move accumulated sludge from the manway. The device also allows technicians to inject chemicals, scavengers, and emulsion breakers into the tank to begin the breakdown of sludge.



Over the years, tanks have been outfitted with various mixing devices, such as propellers, designed to suspend particles and discourage waxes and sludge from forming. However, some of the devices tended to simply push the wax and sludge away from the propeller, as it formed along the circumference of the tank.

The company promotes the use of its own DS Jet Mixing System, a patented, oscillating nozzle mounted permanently on the AST’s manway. The device sends a high-velocity stream of diluents into the sludge, shearing and re-suspending wax molecules so the hydrocarbons remain usable.

“The appeal of the jet mixing process we use is that we can typically recover more than 90 percent of the usable oil from the sludge,” says Heath. “Removing the fluid from the sludge not only reduces the amount of waste you need to dispose of, it provides a revenue stream from the recovered oil. It also reduces tank maintenance and downtime.”

The jet mixer is mounted permanently in the tank at the start of the contract, with Allerion retaining exclusive rights as the device’s licensed activator. Clients opt to go with the technology on about 70 percent of contracts.

“Jet mixing also improves safety by minimizing the time that workers spend inside the tank,” Heath says. “Instead of manually removing four feet of sludge, you’re dealing with perhaps four inches.”

Once the tank has been emptied as far as possible, it’s vented in preparation for human entry and a final manual cleaning. Safety is paramount. Workers don protective equipment, including rubber rain gear, cartridge face masks, or face masks with supplied air. Heath says the company has registered no lost-time incidents since 1998.

The remaining sludge is scraped from the tank and removed with the hydraulic scoop, floating roof pontoons are wiped down and the tank is given a final diesel wash.



Heath says he’s looking to expand the company using the same deliberate approach Allerion applies to tank maintenance. The company’s sustainable growth model includes measured expansion, a balanced approach between service and equipment sales, and a careful employee selection and training process.

“It’s really easy to cast an eye to new business and to quickly chase it,” says Heath. “If you grow too fast, when a downturn comes you’ll end up with a workforce of unsuitable labor that you hired too quickly. When downward pressure on profit margins occurs, you’re really in a bind.”

While business depends on the level of activity in the resource sector, Heath notes that all ASTs containing oil will eventually need to be serviced.

“During the last downturn, we found the lag between the downturn and the decrease in maintenance budgeting at about 18 months,” says Heath. “But even if you defer maintenance, the regulations will eventually catch up with you. We’ve developed what we believe to be a sustainable business model, so if the price of oil drops from $145 a barrel to $40 during a downturn, we won’t be caught flat-footed.

“Our horizon isn’t the next year or the next five years – it’s 10 or 20 years.”

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