This article describe the requirements and specifications for workshop intended to support well services operations.

The work undertaken by a typical workshop may include:

• quality assurance checking of new equipment;
• pressure testing of equipment;
• make-up and testing of new sub-assemblies;
• valve testing;
• testing and calibration of bottom-hole pressure/temperature survey equipment;
• maintenance, setting and testing of gas lift equipment;
• maintenance of wireline tools and surface equipment;
• ensuring that all items used meet the various specifications. 

Additionally, the workshop plays an important role in the investigation and analysis of equipment failures. A well-run workshop, provided with all necessary facilities, should enhance the well servicing operations and thus minimise loss of production.

1. Layout

When planning the layout of a workshop, the following should be taken into account:

• The movement of heavy equipment.
• Free access to all the facilities of the workshop
• specific areas requirement for tools returning from field, cleaning, maintenance/ inspection, storage.
• Safe areas for pressure testing must be established.

2. Equipment, general

The following items of equipment are considered necessary in order to undertake general workshop operations:

• Test pump unit, air-driven with 5000 and 10,000 lb/in2 test systems. The unit should be equipped with low pressure/high volume pre-fill pump and accumulators fitted with high pressure relief valve circuits.
• Make-up and break-out torque machine capable of handling minimum and maximum sizes of tubulars, e.g. 2 7/8" to 7".
• Swivel-mounted tubular vices and pipe stands.
• Bench-mounted grinding machine.
• Martin Decker or Foxboro type portable pressure recorder.
• Portable air-driven wire bush for cleaning purposes.
• Horizontal storage racks inside and outside the workshop for storage of tubulars such as sub-assemblies, pup joints, etc. (preferably wall-mounted).
• An overhead travelling crane.
• Vacuum pump for testing valve balls, flappers and seats.
• Standard flat-jaw and tubular vices.
• Equipment cleaning baths.

3. Specialised equipment

Some of the items of specialised equipment which may be considered are:

• Amerada test and calibration temperature bath and dead-weight tester.
• Gas lift valve test and calibration equipment.
• Durometer for elastomer hardness checking.
• Hardness tester (Rockwell, Brinell, etc.) for metals.
• Thread/profile comparator.
• NDT equipment (flaw detectors, eddy-current detectors, etc.).
• Inspection equipment such as:
• inside and outside micrometers;
• Vernier calipers;
• depth indicators, etc.

4. Lifting equipment

All lifting equipment must be inspected and tested on a regular basis, and records kept showing dates of tests, repairs, modifications and maintenance carried out, and by whom.

The above inspection and testing not only applies to workshop lifting equipment, but equally to field operational wireline equipment.

All lifting equipment must be listed in a register, and each item must be stamped with its own unique number.

5. Access

Access is an important factor to be considered in the layout of a workshop.

6. Principal operations

The workshop undertakes many tasks in support of well servicing operations.

• equipment procurement;
• make-up of sub-assemblies;
• inspection;
• testing and calibration;
• overhaul and repair;
• certification.

6.1 Equipment procurement

Replacement of unserviceable equipment and acquiring additional new equipment to meet changing demands is generally part of the service provided by the well services workshop.

6.2 Make-up of sub-assemblies

A workshop makes up completion sub-assemblies from their component parts in accordance with requirements. This may not be possible at the well-site because of lack of facilities. Completed sub-assemblies are normally ready for immediate use on leaving the workshop having been drifted, functionally checked, operated, and pressure tested.

6.3 Inspection

No item of wireline or sub-surface equipment should be used in the field which has not been thoroughly inspected in the workshop, in order to prevent unnecessary delays at the well site.

Items such as link (spang) jars, hydraulic jars, knuckle joints, thread connections and all toolstring components utilised in H2S service should regularly undergo crack detection inspection.

6.4. Testing

Testing forms a large part of the work undertaken by the workshop. It supplements inspection to ensure items are suitable to meet the design requirements of the well, and can play an important role in the investigation and analysis of equipment failures. Testing must ensure that the item being supplied for use in the field conforms with the appropriate specification under which it was procured.

6.5  Pressure/vacuum testing

The pressure tests can range from low pressure leak testing of joints to full rated pressure tests of components, and may be carried out on new equipment as a specification check, as a periodic requirement for such items as lubricators, or on repaired/refurbished equipment.

Following testing, the items should be clearly marked with a stainless steel band or label which tabulates the working pressure, test pressure, date of test and service (H2S or Normal).

Critical items of equipment should also be checked for wear, cracks and wall thickness and be appropriately colour coded.

6.6 Functional testing

Functional testing must be applied to all items which have moving parts, such as sliding sleeves and safety valves.

6.7 Gas lift valve charging and testing

It must be appreciated that the efficiency of a gas lift installation depends upon being able to predict the performance of the gas lift valve operation in the installation. If the operating pressure settings alter and become scrambled in the well, the installation cannot be expected to perform as designed with a subsequent loss in production.

For testing the setting pressure of tubing sensitive (fluid operated) gas lift valves, both casing and tubing pressures must be simulated on the test equipment.

6.8 Overhaul and repair

After overhaul and/or repair, each item must be inspected and tested as appropriate, to ensure that it again conforms to specification and can be re-used. It is for this reason that manufacturers' performance data, as well as maintenance and assembly tools, jigs and instructions should be readily available, and these should always be ordered with the original equipment.

6.9 Certification

It is the responsibility of the well services department to ensure that all items of surface and sub-surface well services equipment are inspected, tested and maintained in accordance with the appropriate certification requirements.

7. Safety

Many of the activities undertaken in a workshop, such as moving heavy items of equipment and pressure testing, are potentially hazardous to personnel and equipment. It is essential that these hazards are minimised as far as possible. This can be achieved by careful design of the workshop layout, by the establishment of safe working practices, and by the alertness and training of workshop personnel.

In the final analysis, the safety of personnel and equipment depends upon the skill and judgement of the workshop personnel themselves. It is the responsibility of the Workshop Supervisor to ensure that workshop personnel have received all necessary training and are competent to undertake any task assigned to them. Only fully trained personnel should be allowed to work without direct supervision.

8. Storage and preparation for shipment

All items of equipment should arrive in the field serviceable and ready for use. Damage during storage and transportation must be avoided. This can be achieved by adequate protection being applied immediately the item is finished in the workshop.

Finished items should be stored away from workshop activity and accessible for loading and transportation.

SSDs, SCSSVs, packers, travel joints and swivels, especially in the larger sizes, should be stored with their longitudinal axis in the vertical plane. Such an arrangement will ensure that elastomers in the form of "O"-rings. "T"-seals and "V"-packings are not permanently deformed by weight, thereby curtailing their sealing function.

The open ends of tubular sub-assemblies and other similar items must be capped or plugged, and ports must be taped over, to keep them clean from foreign objects and dirt.

Large tubular items should be stored off the floor and supported at several points along their length; it should not be possible for these items to knock against each other during transport. Items which external seals should be treated with special care, the seals must be protected, preferably by a purpose built, rigid container. Smaller items should be stored and transported in containers in which they will be protected by being clamped or padded. Lubricators and lubricator components are to be fitted with blank quick unions or protectors to prevent thread damage and ingress of dirt.

Particular mention should be made with respect to the storage of elastomers, due to their susceptibility to ultraviolet light and temperature. It is preferable, especially in tropical areas, to store all elastomers, completion equipment such as SSDs and packers which contain elastomers, in air-conditioned rooms/stores.

9. Servicing records

Detailed records of all work performed, technical data, inspection and test results in the workshop must be kept. It should be possible to locate any piece of equipment easily and quickly, and determine its current status. In many cases this may be a requirement by local authorities, such as for SSSVs.

10. Gauge room

An air-conditioned store room must be available.