Workover and well intervention equipment for planned field tasks.

Operating requirement

Start with the well task, not only the horsepower.

Workover equipment selection should begin with workover depth, tubing or drill pipe size, required hook load and the type of intervention planned. Mobility and site access are equally important when the rig will move between scattered wells or remote locations.

Step 1: Sort the workover range by depth and hook load.

The workover rig line steps from a 150HP entry model to an 850HP ultra-heavy class, and the published figures show where each model sits. The workover depth is quoted for 2-7/8 inch upset tubing, so it reflects the actual servicing envelope rather than a drilling rating:

Workover rig range (published figures)

Model	Workover depth (2-7/8" tubing)	Max. hook load	Mast height	Engine / transmission
150HP	2600 m	585 kN	18 m	6×4 chassis
250HP (XJ250)	3200 m	675 kN	21 / 23.5 m	6×4 chassis
350HP (XJ350)	4000 m	900 kN	23.5 m	10×8 chassis
450HP (XJ450)	5500 m	1125 kN	32 m	CAT C15 / 540 bhp, Allison M5620AR
550HP (XJ550)	7000 m	1350 kN	34 m	CAT C18 / 630 bhp, Allison M6620AR
650HP (XJ650)	2000 m drilling (4½" DP)	1470 kN	35 m	CAT C18, Allison M6620AR
750HP	8000 m	1800 kN	38 m	Dual CAT C15, dual Allison M5620AR
850HP	9000 m	2250 kN	39 m	Dual CAT C18, dual Allison M6620AR

Below 450HP the rigs use a two-column moving envelope around 13.9 m long and 31.5 t, with the mast height rising through the range; from 450HP upward the published rating switches to engine and transmission detail, which matters when the buyer compares fuel, service parts and drive redundancy.

Step 2: Read the chassis and the mast against the road and the wellhead.

A truck-mounted workover rig is a road unit first. The 350HP model runs a 10×8 chassis and the 750HP and 850HP models run 14×8 all-terrain chassis, which raises the turning radius and the axle loading that the operator must confirm against the route. The mast clear height, from 18 m on the 150HP model to 39 m on the 850HP model, also decides the headroom needed at the wellhead for the tubing and the travelling equipment.

Step 3: Separate workover depth from drilling duty.

Some models publish a drilling column as well: the 650HP rig is rated 2000 m on 4-1/2 inch drill pipe, and the truck-mounted rig series extends this to 3000-4000 m in the 750HP and 850HP classes. When the same unit will drill and then service the well, compare the drilling depth against the workover depth separately, because the two ratings use different pipe and different duty cycles.

Step 4: Add intervention support units to the spread.

Routine well intervention is usually a spread, not a single unit. The coiled tubing truck series covers three pulling-force grades up to 290 kN with a maximum laying-down depth of 5900 m, the wireline unit handles wireline work to about 6000 m on 2.4 mm line, and the swabbing unit reaches a working depth of 3350 m with a drum lifting capacity of 80-120 kN. State the intervention method in the inquiry so the rig, the support unit and the well-control scope are quoted together.

Step 5: Confirm the operating envelope in the inquiry.

Send the target workover depth, the tubing or drill pipe size, the expected maximum lifting load, the intervention task and the relocation frequency. The supplier then matches the rig class, the chassis and the support units, and confirms the documentation and commissioning scope in the quotation.

Step 6: Confirm the moving envelope and the road permit.

A truck-mounted workover rig must reach the well under its own power, so the moving dimensions and the curb weight belong in the selection review. The published figures for the light end of the range are concrete: the 150HP model travels at 10,590 × 2,490 × 3,950 mm with a curb weight of about 22,770 kg, and the 250HP and 350HP models travel at 13,910 × 2,705 × 4,320 mm with a curb weight of about 31,490 kg. The height including the mast, roughly 3.95-4.32 m in this part of the range, becomes the binding constraint on routes with low bridges or overhead lines, while the axle configuration (6×4 on the lighter models, 10×8 on the 350HP, 14×8 on the 750HP and 850HP) drives the road permit and the turning behaviour. Ask for the loaded dimensions, the turning radius and the axle loading in writing, and compare them against the actual routes before a model is committed to a lease.

Step 7: From the operating requirement to the quotation.

A workover inquiry is complete when it names the well depth and tubing size, the intervention task, the expected maximum load, the relocation frequency and the support units. With those inputs the supplier matches the rig class and the chassis, confirms the mast and the moving envelope against the site, attaches the coiled tubing, wireline or swabbing units required by the intervention method, and returns the quotation with the documentation and commissioning scope. Keeping the comparison on published parameters also makes the same inquiry comparable across suppliers.

Step 8: Commissioning, spares and operator training complete the package.

Once the rig class and the support units are fixed, the remaining scope items decide whether the package can be operated at the well site. Confirm the documentation set (operation and maintenance manuals, factory test reports, loading documents), the recommended spare-parts list for the first operating period and the commissioning support. For truck-mounted rigs, the chassis service items, the drawworks brake wear parts and the wireline are the consumables that drive the early operating cost, so ask for the maintenance schedule alongside the quotation. Where the operator team is new to the model, agree the operator training scope and the on-site commissioning crew with the supplier. These items do not change the published depth and hook load, but they determine how quickly the rig reaches working condition on arrival and how the first operating period is supported, which is the practical difference between a specification sheet and a field-ready unit.

For operators running several wells on one block, standardising the workover fleet on one chassis and driveline family, as the 250HP to 850HP range does, simplifies crew training, spare-parts stocking and maintenance scheduling across the rigs. When the tender allows separate line items, propose the rig, the support units and the moving system as separate scoped lines so the owner can compare each element against the operating plan and against competing bids on equal terms.

When the well programme is dominated by one intervention type, such as tubing service across a block, matching the fleet to that single task and standardising the support units reduces both the capital outlay and the logistics between wells. State the planned well count and the service window so the supplier can also size the fleet rather than a single rig.

The same comparison logic applies when the tender covers several leases: list the well depth, the intervention task and the service window per lease so the fleet proposal follows the actual workload.