Oil Well Workover Rigs: How They Work
An oil well workover rig is a specialized drilling rig designed to service and maintain oil and gas wells. It's not for drilling new wells — it's for fixing and improving existing ones. Workover rigs are essential to the oil and gas industry, because every well needs regular maintenance, and without workover rigs, most wells would stop producing within a few years.
The Main Components
A workover rig has several key components:
The Mast. This is the tall tower that holds the drill string. On workover rigs, it's usually a telescopic mast that folds down for transport. The height of the mast determines how long a stand of tubing you can pull at once, which affects how fast you can trip in and out of the hole.
The Drawworks. This is the winch that raises and lowers the drill string. It's the most important piece of equipment on a workover rig. The size of the drawworks determines how much weight you can pull, which determines how deep a well you can work on.
The Power System. This is the diesel engine that powers the whole rig. It drives the hydraulic pumps, which power the drawworks and all the other functions. Most modern workover rigs use hydraulic drive, which gives you precise control over speed and torque.
The Control Cabin. This is where the driller sits to operate the rig. Modern workover rigs have air-conditioned control cabins with comfortable seats, good visibility, and all the controls within easy reach.
How a Workover Job Works
A typical workover job goes like this: you drive the rig to the well site, set it up, and rig up to the wellhead. Then you pull the tubing out of the well, one stand at a time. Once the tubing is out, you do whatever work needs to be done — replace the pump, perforate a new zone, fix the casing, whatever. Then you run the tubing back in, rig down, and drive to the next job.
FAQ
Q: How long does a workover job take?
A: It depends on the job. A simple pump change might take 1-2 days. A more complex workover — like fishing or casing repair — might take a week or more. The depth of the well also matters. Deeper wells take longer, because you have more tubing to pull and run.