July 1, 2009

Extreme Oil Changes

Drew Robb

Performing regular oil changes on remote generators is far from simple or cost-effective. Here’s how one firm harnessed technology to extend oil change intervals from one week to two months.

For most people, an oil change means dropping into the local Jiffy Lube or repair shop and driving away 15 minutes later. For Dennis Fleming, manager of the Valleyview branch of Tarpon Energy Services Ltd. of Calgary, Alberta, that isn’t an option. Tarpon provides diesel generator sets, primarily to companies working in the Canadian oil patch, and maintains units up to 700 kilometers away from his headquarters.

"It is not uncommon to drive for hours to do a 20-minute oil change, then hop in the truck and drive back," said Fleming. "There is no way of getting around that when dealing with these remote locations."

To make matters worse, some locations can’t even be reached by truck. "We have even had a couple jobs in northern Alberta where we were helicoptered in and out for one whole summer just to change the oil in the unit," he continued. "Our guys were pretty excited about the helicopter rides."

Raising Reliability

Tarpon leases more than 200 Cummins diesel generator sets in sizes ranging from 20 kW up to 1 MW. The units are mostly used by oil companies to get a well site up and running until line power is brought out to the site, though some locations are too remote to ever connect to the grid. Fleming says that most well sites use the 100-kW generators to power the surface pumps or the down-hole submersible electric pumps. The smaller units might run lights, heaters, and electronics at a site, while the megawatt-scale generators would be used at new batteries facilities where the liquids obtained from one or more wells are stored for initial processing before being sent to the refinery.

The oil producers rely on the generators to always be available. Even a momentary power glitch will cause the electronic systems running the down-hole pumps to shut down, requiring a manual restart. If that happens during dinner or overnight, the wells can fill with sand. "At that point, they will have to bring a service rig in and pull the pump, clean out the well, put the pump back down, and hope it works," said Fleming. "It is quite a costly venture for them."

For most applications the staff works on improving the reliability of the diesel engines. Many locations have a backup generator, in case one goes down, which also makes it easier to schedule maintenance. They have also doubled up on fuel filters and installed more inline fuel filters. Designing buildings with better airflow is another option, so that bugs, dirt, dust, and pollen don’t clog the radiators.

The biggest area for improvement, though, is with engine oil. As built, the generators required a weekly oil change. Adding additional oil filtration equipment extended the oil life to 350 hours, about two weeks. This was better, but still not good enough or cost-effective for those servicing the engines. It was also difficult to schedule changes that frequently. Tarpon would have to coordinate with the technicians and the oil company representatives at the locations, and due to schedule conflicts, the oil changes would usually end up going over that 350-hour margin.

"It is simply too often to be shutting down their system, especially if they have trouble starting them up again," said Fleming. "So I asked the people in my division to start looking for a way to manage the short time frame maintenance issue."