OOO “SNK” Service: Well Maintenance

Well maintenance includes the set of measures, which allow restoring well productivity and the possibility of its operation, and performing the rehabilitation or replacement of downhole and wellhead equipment. In addition, during the maintenance the bottom and the eductor are cleaned of accumulated deposits and obstructions, as well as the intensification of the reservoir productivity and the BHT.

Maintenance can be:

• Preventive (prophylactic), the purpose of which is to prevent the planned operation mode of equipment and well production schedules from deviations; inspection of equipment;
• Overhaul (recovery), caused by the sharp deterioration of technological parameters or failure of equipment. Overhaul, in fact, is an emergency and requires the use of more sophisticated technologies.

Groups of Work during the Maintenance

The workers carry out the following operations during the maintenance:

• transport operations, including equipment and maintenance crew delivery to the well;
• preparatory (killing of the well, assembly and disassembly of wellhead equipment);
• lowering lifting reconstructions;
• cleaning of wells from sand and salt blockages, removal and replacement of components and worn-out equipment, application of methods of reservoir delivery recovery (warm, flushing, introduction of chemicals), running well into the working mode of operation;
• the final (equipment dismantling, preparing it for transportation, cleaning the work area).

IMPORTANT: When carrying out well operation near the bottom zone, comprising semi-consolidated rocks, an intense sand slugging is often observed, causing the collapse of the bottom zone and the deformation of the casing. In addition, blockages density can be several hundred meters. This phenomenon must be removed immediately to avoid suspension or even complete cessation of oil flow (outflow of wells).

OOO “SNK" successfully applies a variety of methods for plugs removal, including

• direct water flushing;
• the application of bailer and hydrodrills, lowered into the well on a rope. Pipeless hydrodrills operation is similar to a repeated action bailer, and the tool consists of three units (the bit to break the rock, bailer to collect drilled cuttings, plunger pump to provide recycling in the well), weighted with thick-walled tube. The bore cleaning is quite long and time-consuming.

OOO "SNK" provides the following options for wells maintenance:

• putting wells into operation with original equipment (flowing wells, gas-lift wells, using centrifugal pump units (ESCPs) and rod pump;
• conversion of oil well to another way of use, including all existing options (flowing to gas-lift, rod pump, ESP; gas-lift to rod pump, ESP; rod pump to ESP; rod pump to dual completion, etc.)
• cleaning and washing the bottom and the wellbore to intensify. Hot oil with the addition of surfactants is used as a washing reagent, hydrochloric acid treatment of advanced reagents is applied as well, thermochemical gas impact, thermal steam treatment, reactant treatment with solutions;
• full service of flowing wells, including inspection, replacement of wellhead equipment, molding and restoration of well integrity;
• achieving optimal technological parameters of well delivery (calculation of sizes of rod pumps and ESP, and the setting depth);
• installation, repair and maintenance of wells with rod pumps (preventive maintenance and replacement of sucker rod pump, removing the broken rod, replacing the broken rod in the pump, control of abutment of the plunger to the cylinder walls, the elimination of the polished rod defect for pump’s normal operation, cleaning, steaming and processing of wellhead equipment.

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