Most of the work that is needed to commission wells is associated with lowering downhole pumps, compressor pipes, and pump rods into them. In the process of their activity, various breakdowns can occur. Regardless of the method of operation (compressor or pump), in the event of a malfunction, the pressure drops sharply or the fluid supply stops completely. Depending on the complexity of the breakdowns, maintenance and workover of wells is required to resume full-fledged activities.
Restoring normal operation is associated with lifting equipment from underground to the surface for repair, eliminating breaks and unscrewing pump rods. An important role is played by the cleaning of sand plugs by washing or bailing.
Repair of wells due to violation of their technological mode of operation includes:
- replacement of tubing with analogues of a different diameter;
- changing the length of the lifting pipes;
- eliminate the breakrods;
- replacement of wellhead equipment;
- installation of electric centrifugal pumps.
But this is not a well workover. All of these works are ongoing activities. They are carried out by special teams that deal with underground troubleshooting. Well workovers are more complex and large-scale activities. These include:
- elimination of accidents associated with breakdowns of the casing string (collapse or breakage);
- removal of water that appeared in the well;
- work related to the transition to another horizon;
- catching broken cables, pipes, tether lines and other equipment.
The overhaul of wells is carried out by special teams. The main task of the personnel who are engaged in ongoing work and other field workers is to contribute to the reduction of the terms of these activities and the maximum increase in the uninterrupted service life of the well during its operation. The overhaul period is the duration of the actual normal operation of the equipment, that is, the period between two scheduled repairs.
To increase the intervals of this time, properly conducted underground and workover wells are extremely important. To ensure business continuity, ground and underground activities are combined. In the fields, schedules for such events are drawn up in advance.
Based on the ratio of the actual time of productive work to the total number of calendar days in a certain period (quarter, year, etc.), such an indicator as the operating coefficient is displayed. Its value is always less than one. On average, at oil and gas production enterprises, it ranges from 0.94-0.98. That is, 2-6% of the time is spent on various types of repair activities.
The brigades that carry out current repairs, as a rule, include three people: the operator at the mouth, his assistant and the tractor driver who controls the winch. They usually work on a rotational basis. Well workover is carried out by special teams, which are part of various service departments and enterprises of gas and oil companies.
