Current and workover of wells

Most of the work needed to put wells into operation is associated with the descent of deep pumps, compressor pipes, and booster pumps. In the course of their activities, various breakdowns may occur. Regardless of the way of operation (compressor or pump), if the normal operation is disturbed, the pressure drops or the supply of liquid stops completely. Depending on the degree of complexity of breakdowns for renewal of full-fledged operations, current and major repairs of wells are required.

Restoration of the normal operation mode is associated with the lifting of equipment from under the ground to the surface for repair, by eliminating the breaks and unscrewing of the pumping rods. An important role is played by cleaning from sand plugs by rinsing or bailing.

Repair of wells due to a violation of their technological mode of operation includes:

• Replacement of tubing with analogues of a different diameter;
• Change in length of lifting pipes;
• Elimination of broken bars;
• Replacement of wellhead equipment;
• Installation of electric centrifugal pumps.

But this is not a major repair of wells. All these works are related to current events. They are carried out by special brigades, which are engaged in underground removal of breakages. Overhaul of wells is more complex and large-scale measures. These include:

• Elimination of accidents associated with casing failure (crushing or breakage);
• Drainage of water that appeared in the well;
• Work associated with the transition to another horizon;
• Catching broken cables, pipes, tartal ropes and other equipment.

Overhaul of wells is carried out by special teams. The main task of personnel engaged in ongoing work and other fishermen is to help reduce the time of these measures and maximize the uninterrupted service life of the well during its operation. Overhaul period is the duration of the actual normal operation of the equipment, that is, the time between two scheduled repairs.

To increase the intervals of this time, well-grounded and overhauled wells are of critical importance. To guarantee the continuity of work, ground and underground activities are combined. Schedules of such events are prepared in advance on the fields.

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.), an indicator such as the operating ratio is output. Its value is always less than one. On average, it fluctuates between 0,94-0,98 at oil and gas production enterprises. That is, 2-6% of the time is spent on various types of repair activities.

The brigades that carry out routine maintenance, as a rule, consist of three people: an operator at the mouth, his assistant and a driver-tractor driver running the winch. Usually they work on a rotational basis. Capital repairs of wells are carried out by special teams that are part of various service departments and enterprises of gas and oil companies.