Shallow well workover: a package built for high well counts and short cycles.

Operating model

Size the package for the way shallow fields are operated.

Shallow and mature fields are usually operated as a large well count with short service cycles. The typical job is a tubing change, pump repair, flushing, paraffin removal or a light stimulation, and the rig is expected on site within days and gone within a week. That operating model changes the equipment decision: the purchase is not driven by the deepest well in the field but by the move count and the service speed. A deep-service rig on a shallow field pays for mast, drawworks and chassis capacity that is never used, and it takes longer to rig up and move.

The ZYT shallow well workover package covers this duty with the 150HP, 250HP and 350HP truck-mounted workover rigs plus the well service support fleet, all matched to the same depth band and priced as one scope.

Step 1: Match the rig class to the well depth and the service load.

The shallow package starts with the rig class. The 150HP rig carries a 585 kN maximum hook load on an 18 m mast; the 250HP XJ250 carries a 400 kN nominal and 675 kN maximum load on a 21 m or 23.5 m mast; the 350HP XJ350 carries a 650 kN nominal and 900 kN maximum load on a 23.5 m mast with a 10×8 self-propelled chassis. For tubing change and pump repair work down to about 3,000 m, the 250HP class is the usual core; the 350HP class adds reserve for heavier strings and occasional deeper interventions, and the 150HP class covers the very shallow and frequent jobs where the smallest footprint is worth more than the extra margin.

Shallow well workover rig classes (published figures)

Model	Workover depth	Max. hook load	Mast	Chassis
150HP	2,600 m	585 kN	18 m	6×4
250HP XJ250	3,200 m	675 kN	21 / 23.5 m	6×4
350HP XJ350	4,000 m	900 kN	23.5 m	10×8

For the shallow depth band, the published depth figures are stated for a tubular size (2 7/8" upset tubing or 73mm tubing). Confirm the same measurement basis when comparing models, because a depth figure quoted for a lighter string is not directly comparable to one quoted for a heavier string.

Step 2: Count the moves and let the chassis pay for itself.

The commercial argument for a truck-mounted shallow package is the move count. Each self-propelled move avoids the crane and trailer hire, the road permits where they apply, and usually a full day of rig-up and rig-down labour. Estimate the annual move count for the field, write down the per-move saving, and multiply the two: if the result reaches the price difference between a truck-mounted and a skid-mounted rig within two or three years, the chassis pays for itself. In mature fields with dozens of wells and service cycles measured in weeks, that calculation usually falls clearly on the truck-mounted side.

The 350HP XJ350 moves on a 10×8 chassis and the 450HP and larger classes on 12×8 all-terrain chassis, so confirm the axle configuration and the loaded height against the roads and bridges on the route before committing the class. If the field roads are very tight, the 150HP and 250HP units on 6×4 chassis have a smaller footprint and lighter road load.

Step 3: Add the service fleet for one-mobilization jobs.

The rig handles the hoisting, but the shallow well job is completed by the service fleet. The standard package includes the well flushing and paraffin removal truck for flow-line and tubing maintenance, the swabbing unit (with swabbing tool) for production testing and unloading, and the boiler truck for hot-oil and heat work. For wells with wireline requirements, the wireline unit is added; for larger fluid volumes, the fluid supply truck (rated 750 m3/h at 45 m head) supports the flushing and tank work; and for multi-well programmes, the mobile workshop keeps the fleet running in the field instead of returning to base for repairs.

Support fleet for the shallow well package

Unit	Duty	Typical package role
Well flushing & paraffin removal truck	Flow-line and tubing flushing, wax removal	Standard
Swabbing unit / tool	Production testing, unloading	Standard
Boiler truck	Hot-oil work, heat for paraffin jobs	Standard for waxy fields
Wireline unit	Logging, perforating support, gauges	Optional
Fluid supply truck	750 m3/h water and fluid supply	Optional
Mobile workshop	Field repairs and maintenance	Optional, multi-well programmes

Step 4: Check the well-control and environment requirements.

Shallow wells still carry well-control obligations. Confirm the BOP fit against the mast clearance and the rig floor layout, and state the wellhead and casing programme in the inquiry so the supplier can confirm the substructure and the well-control fit. For the operating environment, confirm the temperature range and the dust or corrosion treatment: the rigs are configurable for desert, plateau and cold-region service, and the 350HP class in the truck-mounted line is rated for continuous duty across -20°C to +55°C with cold-start and heat-dissipation options for extreme sites.

Step 5: Price the package per line item and confirm the support terms.

Request the package as line items so the boundary is visible: rig, service trucks, tanks and manifolds, documentation and spares. Confirm the certification level that applies to the exact configuration, the commissioning scope and the spare-parts list for the first operating period. A package quotation from one supplier keeps the interfaces, the documentation set and the commissioning plan consistent, which is worth more in a high-move-count operation than the difference between two single-machine prices.

What to send for a shallow well package quotation.

Send the field profile: the number of wells, the typical depth and tubing size, the service cycle and move frequency, the task list (flushing, swabbing, paraffin removal, wireline or light drilling), the road and site conditions, the quantity of packages, the destination port and the required documentation. With the field profile, the supplier can match the rig class, the service fleet and the spare and support terms as one shallow well workover package.