It is more important than ever to reduce the frequency and extent of workover operations whenever possible. Pulling a failed electric submersible pump (ESP) requires a heavy workover, and with the ongoing challenge of rig availability, especially in the Middle East, operators are looking for ways to avoid or minimize the occasions that a rig is required. Typically, replacing an ESP involves taking a rig that is drilling and halting the drilling program to pull the broken ESP. ESP-related production downtime is a common and costly problem. Consequently, some operators are investing significant time and resources in investigating ways of reducing the revenues lost when changing out their ESPs. Some goals operators are working toward are obtaining ESPs with a 10-year life cycle and ESP replacements that can be started and completed in only one day.

AccessESP works to support operators in achieving these goals through its rigless slickline ESP deployment system. Retrievable ESPs can reduce replacement times and eliminate the need for a rig to be onsite to perform a heavy workover. The ability to replace the ESP with a slickline unit delivers a variety of benefits for the operator. Costs are reduced, complexity is eliminated and downtime is minimized.

Development of a rigless system

The development of the rigless slickline ESP deployment system had its origins in a system that had been in use for about 20 years. This initial system featured an ESP pump, pack-off and tubing stop that could be pulled and replaced with slickline, thus providing positive improvements to well uptime in areas where pump wear is an issue. The current deployment system is a four-run retrievable system: motor, pump, pack-off and tubing stop. Instead of a rig or heavy workover unit, the AccessESP system allows an ESP to be replaced in a live well through tubing using conventional lightweight readily available slickline equipment. It is no longer necessary to consider an ESP as a part of a completion string that must be pulled whenever there is a need to intervene in the well or to replace a failed ESP component or system.

When the components are out of the well, there is a fullbore path to allow well work to be accomplished below the ESP setting depth. In several cases sand plugs have been observed below the ESP, and by pulling the ESP components the wellbore obstructions were easily removed and the well returned to production. By designing the system with simplicity at its core, the opportunity for successful retrieval and replacement is increased.

Middle East applications

Operators in the Middle East region are looking to produce their wells as efficiently as possible, and ESPs provide the most efficient artificial lift method. The AccessESP system recently underwent a program in a live well application under real operating conditions.

The integration program was initiated in 2016 to qualify the technology for potential full field implementation in the operator’s wells. During the initial 2016 operation a failed conventional ESP was pulled and replaced with the AccessESP “dock” (wet-mate connector). The complete retrievable system (motor, pump, pack-off and tubing stop) was installed through tubing in a conventional slickline operation. As part of the program the retrievable system was immediately pulled and reinstalled.

In February 2017, after six months of operation, the retrievable system was again retrieved and replaced in a live well using conventional slickline equipment and operations. The key success criteria for the program, as identified by the operator, have been achieved to date. These include deployment and installation of the dock, commissioning and multiple retrievals, and re-installations of the ESP on slickline.

The equipment installed included the Access375 permanent and retrievable systems. The permanent system consisted of an orienting section and a docking station. AccessESP’s proprietary dry-mate connectors were used to enable connection to surface via a conventional ESP power cable. The dry-mate connector increases quality and reliability of the system since it is factory-installed on the cable. This leads to rig time reduction during installation and removes one field splice.

The retrievable system includes a 250-hp permanent magnet motor, a 19.2-m (63-ft) 400 series ESP pump, a pack-off and a tubing stop.

The AccessESP permanent magnet motor operates with any commercially available variable speed drive (VSD) motor. In this installation it connected to the VSD on the well with no modifications required. The 400-series pump outer diameter was turned down to 3.80 in. to allow through-tubing deployment in the 4½-in. tubing.

No changes were needed to the horizontal wellhead configuration. The program demonstrated that the ESP can be slickline- deployed without killing the well while remaining fully compliant with rigorous safety policies, well control barrier philosophy and slickline operating procedures. This is accomplished without a downhole lubricator valve or deepset safety valve using standard ESP completion designs.

The system is compatible with 7-in. casing, producing up to 6 Mbbl/d through 4.5- in. tubing using 3.75-in. permanent magnet motors up to 400 hp. Higher flow ratings (to 20 Mbbl/d) and power ratings (to 1,300 hp) are available in larger tubing sizes.

This deployment system delivers significantly reduced ESP operating cost, simplifies field logistics and increases production per well through reduced ESP downtime.

A slickline-deployed live well intervention system requires no changes to well control procedures. It is the only system that allows the change of only the pump while leaving the motor in the well connected to the permanent completion. As a result, further time and cost savings are delivered with significantly reduced HSE exposure and risks.

AccessESP’s system is unique in that it can be deployed with slickline. When retrieved with slickline, the permanent completion has fullbore pass-through to allow well work below the ESP setting depth. The system can be integrated with any ESP pump provider and can utilize any ESP surface drive in the market. No special surface equipment is needed. It also can be deployed at high inclinations, unlike other systems.

Building on success in the Middle East, additional operators in the region are also recognizing the need for reducing the time and cost to replace a failed ESP sysA rig worker runs the AccessESP tool into a well. (Source: AccessESP) tem with the rigless method.