The Y-tool is a solution to enable production-logging and well intervention below a working ESP at any point in time during production without pulling the completion string. The Y-tool is installed on the production tubing, providing two separate conduits. One conduit concentric with the production tubing and enables access to the reservoir below the ESP. The second conduit is offset and used to support the ESP system. Flow rates in different perforation intervals and other valuable geophysical information could be collected for production optimization and enhanced recovery plans.
With an ESP Y-tool in place, Operators are able to carry out wireline or coiled tubing logging, memory gauge deployment, tubing-conveyed perforation, well treatment and stimulation operations, effectively managing production operations and reservoir performance without pulling the ESP, dual ESP installation and bridge plug setting for water shutoff, etc.
Wireline or coiled tubing plugs can be used to seat in a nipple profile in the Y-tool to enable intervention or logging operation without retrieval of the completion. If required, the ESP can be run with these plugs in place to perform production logging or other well interventions.
The ESP submersible pumping system consists of both downhole and surface components. The surface components are transformers, motor controllers, junction box and wellhead.
The wellhead accommodates the passage of the power cable from the surface to the wellbore.
The main down-hole components are the motor, seal, pump, and cable. Additional accessory equipment may include the gas separators, check and drain valves, cable bands and protectors, and downhole sensors.
Technologies, types, recommended practices and selection criteria of each compound of the ESP pumping system are discussed in the following list of 22 posts.
Junction box, Check and Drain Valves, Downhole Sensor and Centralizers are some kinds of ESP Accessory Equipment. These type of equipment could play an important role to operate the ESP efficiently and maximize it run lifetime.
The power cable coming from the well is connected to a surface electric cable leading to the switchboard. As seen in the figure below, the two cables are joined in the junction box, also called a “vent box”. The surface cable connects the junction box to the motor control panel and the motor control panel to the secondary side of the transformers.
It is a ventilated, weatherproof box performing the following three important functions:
Provides the electrical connection between the downhole and the surface electric cable.
Vents any gas to the atmosphere which might reach this point due to migration of well gases up the ESP power cable. The venting of gas eliminates the danger of fire or explosion that could happen if gases travel in the cable to the switchboard.
Acts as an easily accessible test point for electric checks of the downhole equipment.
Wellhead Equipment for ESP provides a tubing support and allows the power cable to pass from the surface into the well bore. The wellhead is equipped with a wellhead feed through mandrel or pack-off method. It provides a positive seal around the cable. Wellheads and cable pack-offs are available in various pressure ratings and hanging load capacities.
Wellhead Feedthrough, Penetrator, lower and upper pigtails:
The electrical connection of surface and downhole power cables is detailed in figures below. The tubing hanger holds a feed-through mandrel (also called: well penetrator) equipped with the proper seals. Feed-through mandrel seals contain well pressure and prevent gas leaks at the surface. Power cables are connected to the two ends of this device via their three-phase connectors (also called: lower and upper pigtails).