South of the Border:"Iron rod jerk lines: powering oil well pumps for nearly 150 years "
November 20, 2019
Columnist's note: Travelers in north central Montana are used to seeing pumpjacks (oil wells) dotting the region. Around Oilmont on the way from Whitlash to the I-15 access north of Shelby (on S-343) we pass a sizeable area of small, older-looking oil wells. Some are pumping, others seem to be idle. There's also a lot of abandoned buildings and equipment that were used to produce oil and gas.
East of the town of Oilmont, about two and a half miles on the north side of the highway, there's a couple of metal buildings and some oil tanks. The smaller building has an above ground rod running out to a large block of concrete that is mounted so the block moves up and down. I'd noticed the large chunk of concrete but had never noticed it moving.
A ranching neighbor explained the concrete block is part of a system that provides power to several pumpjacks located around the metal building. It was such an usual looking set up I decided to stop in Oilmont and find someone who could explain what I later learned was called an "iron rod jerk line power system."
I stopped at Phoenix Energy in Oilmont, an oil production company owned by Rick Rice. He operates oil producing wells and provides services to other oil producers. Rice owns and operates the iron rod jerk line system I saw from the highway east of town. Recently Rick Rice took me around to see some of his oil operations. Here's some of what I learned about iron rod jerk line systems (often just called 'rod lines') that power pumpjacks in the shadows of the Sweet Grass Hills.
The Kevin-Sunburst Oil Field
dates to the early 1920's
Referring to a map of the area around Oilmont, Kevin and Sunburst (all towns north of Shelby), Rick Rice pointed to a dot about three miles northwest of the town of Kevin and said, "That was the 'discovery well' (first successful oil well) drilled in 1922 that started the Kevin-Sunburst Field." He added there had been some drilling for gas a few years before. Surrounding areas were developed and an oil boom hit the area from about 1922-1928.
In the boom period Ferdig, Montana started and flourished. By 1983 Ferdig's post office had closed as well as the elementary school and most of the houses where oil workers once lived. Oilmont also boomed with support businesses for the oil patch and services for workers. There was a high school in the town. Now Oilmont is mostly shops for oil patch-related businesses and a few houses.
Iron rod jerk line systems came to the
Kevin-Sunburst Field in the 1920's
The first successful oil well in the U.S. was drilled in 1859 in Pennsylvania. Early on each producing well had a pump powered by its own engine or motor, not a particularly efficient use of power. In 1875 two inventors devised a system that used one power source with multiple rods going to several pumpjacks. That was the forerunner of the iron rod jerk line systems. Soon the rod line power systems were being used in shallow pumps throughout the east.
Rick Rice said the rod line power systems came to the area around Oilmont in the 1920's. "With the wells in this field varying from depths of about 1400 to 2500 feet the rod line systems were very popular." Rice has one rod line operating along the highway about 2.5 miles east of Oilmont and owns two other rod line systems. He said to his knowledge these three system are the last rod line systems remaining in the Keven-Sunburst Field.
A rod line system uses one power source to rotate an "eccentric wheel" which pulls the rods linked to distant pumps at wells and pumps the oil. The weight of the pumpjack machinery, rods and fluid in the tubing pulls the rods back down the well. (see photo of interior of the power house with labeled machine parts). The gear box, sitting on the floor, is turned by an electric motor via a drive shaft. Atop the gear box is the "eccentric wheel" that is attached off-center to the gear drive.
A rod to each pumpjack on the system is attached to the eccentric wheel. The rods go through slits in the sides of the power house and run across the ground on raised "rod stakes" to the pumpjacks at the oil wells. To balance the eccentric wheel as it pulls the rods, the large concrete block (called a 'dummy') is also attached to the eccentric wheel to balance the system. The eccentric wheel has holes to accommodate 17 rods which could provide power to 17 pumpjacks.
The challenges and future of rod
line power systems
Rice explained that while he has some retired rod line equipment he can use for parts, new parts are no longer available. And the systems require lots of maintenance. "Even weather," he explained, "affects the maintenance. Snow and ice builds up on the rods and they come off the stakes that hold them off the ground. We've had rods tear out the side of a building because of ice and snow buildup."
Because the rods constantly rub on the tops of the stakes, there's a lot of lubrication. The tops of the stakes are a special cottonwood that keeps the metal rods from rubbing on the metal stakes. The rods also expand and contract because of temperature fluctuations. Rice told that the turnbuckles where the rods attach to the pumps have to be adjusted as the temperatures change.
On the tour Rice pointed out some abandoned houses near the idle rod line power houses. He explained, "In the old days operators hired and provided housing to 'pumpers' to live on site because of the high maintenance needed for the rod line power houses. He said the winter weather was especially difficult when ice caused rods to go off their regular track and fuels used to freeze.
The heyday of rod line systems ended when electric motors became available. Rick Rice said, "If I live long enough, all my pumpjacks on the rod line systems will be switched to electric." While the system is efficient using only one engine or motor for power, the systems require intense labor and maintenance. That's a commitment and cost that oil producers like Rick Rice are no longer be willing to make.