Saudi Aramco and Baker Hughes completed the first installation of the TransCoil rigless-deployed electrical submersible pumping (ESP) system, which is designed to help operators bring wells on production faster and lower the costs associated with installing and replacing ESPs. Because they can eliminate the need for a rig in fields where availability is a concern or where high intervention costs can limit artificial lift options, operators are said to minimize deferred production and lower their overall lifting costs to extend the economic life of their assets.
Developed in participation with Saudi Aramco, the TransCoil system features an inverted ESP system with the motor connected directly to a new, proprietary power cable configuration, eliminating the traditional ESP power cable-to-motor connection, which improves overall system reliability. Unlike wireline-deployed ESPs, the fully retrievable TransCoil system does not have an in-well “wet connection,” which requires a rig to pull and replace if the wet connection fails.
The power cable design enhances the reliability of the deployment string compared to coiled tubing-deployed ESPs that simply pull the power cable through the coiled tubing. Extensive fatigue testing and thermal growth analysis were conducted at the Baker Hughes Coiled Tubing Research and Engineering Center to enhance materials selection and system design. The TransCoil system cable design also extends the operating range to 12,000 ft (3,658 m), compared to traditional coiled tubing-deployed ESP systems, which are limited to approximately 7,000 ft (2,134 m) because, at greater depths, the weight of the power cable will cause it to collapse inside the coiled tubing, creating an electrical failure.
|The TransCoil rigless-deployed system features an inverted ESP with the motor on top connected directly to the power cable. The design eliminates the motor lead extension entirely, removing the weakest connection in traditional ESP systems. (Image courtesy Baker Hughes)|
The TransCoil system can be installed in 4½-in. to 9-in. casing in wells with flow rates up to 18,000 b/d. In mature offshore fields, where high intervention costs can limit the application of ESPs, the system can be deployed through the existing 4½-in. tubing, which Baker Hughes says saves the time and money required to pull the existing completion. Another advantage of the TransCoil technology compared to wireline-deployed ESPs is that it can be installed through a deviation in the wellbore. This capability allows operators to land the ESP closer to the producing zone for greater reservoir pressure draw down and reserve recovery.
A TransCoil system was recently installed and commissioned in Saudi Aramco’s Khurais field and the first-time rigless operation improved efficiency by reducing installation time nearly 50% over a rig-based installation and further deployment efficiency improvements are expected in the future. Although this initial operation was onshore, offshore installations are planned for this year.
“With a large ESP installation base, including many ESPs installed in our offshore fields, the ability to rapidly deploy ESPs riglessly provides tremendous cost benefits to our overall operations. The TransCoil system is particularly beneficial in our challenging high H2S fields as the premium metallurgy in the system can significantly extend the ESP operational life in harsh environment wells,” says Nasir K. Al Naimi, vice president, Petroleum Engineering and Development at Saudi Aramco.