RIGSDOMRIGSDOM · Workover and well service rigs
Workover and well serviceWorkover and well service rigs
Workover units are judged on different criteria from drilling rigs: how fast they move between wells, how small a location they can work from, and how much of the crew work is mechanised.
What matters in a workover unit
Hook load and depth capacity still matter, but they are rarely the deciding factor. The questions that decide a workover campaign are:
- Move time between wells. A unit that rigs down, moves and rigs up in hours rather than days changes the economics of a fifty-well programme entirely.
- Location footprint. Older fields have tight pads and surface congestion. A unit that works from a 40 ft location can reach wells others cannot.
- Simultaneous move capability. Mast, floor and operator console moving as one assembly removes most of the rig-up labour.
- Power swivel versus rotary. For tubing work, a power swivel with adequate torque is usually more useful than a rotary table.
Typical workover scope
Well service work covers tubing changes, packer replacement, perforating and re-perforating, scale and sand cleanouts, artificial lift installation and pulling, zone isolation, and plug and abandonment. Each has different weight and torque demands, and the unit should be matched to the heaviest planned operation rather than the average.
For abandonment work in particular, check the unit can handle the cement plug programme and the casing recovery loads, which are often higher than the routine workover duty.
Matching units
Common questions
What is the difference between a workover rig and a drilling rig?
A workover rig services existing wells — tubing changes, cleanouts, artificial lift, abandonment — and is built for speed of movement and a small footprint. A drilling rig is built to drill new hole and carries much greater hook load, circulating capacity and well control equipment.
Can a workover unit drill?
Some can drill shallow hole or perform sidetracks, but the circulating system and well control equipment are sized for well service rather than drilling. The programme should decide the unit, not the other way round.
Talk to the desk
Tell us the well, the location and the timing, and we will come back with the units that fit, the delivered price or day rate, and the technical data pack.