Inchworming After Tagging the Ball Proves an Efficient Method for Opening a Completion Isolation Valve with Electric-Line Powered Shifting Tool in Deepwater Gulf of Mexico: A Case Study
Authors: Mauchien Thomas , Clement Laplane , Olivio Amanda 
Published: March 2021

Abstract
An intervention operation in the Gulf of Mexico used a novel method with an electric-line powered shifting tool to reliably locate and latch onto the shifting profile of the intended completion isolation valve successfully completing the shifting operation.
Locating and latching onto the lower shifting profile of a completion isolation valve is often a challenging operation with slickline or conventional electric-line shifting tools. It relies on the weight of the downhole tool to provide the downward force to drive the shifter to latch onto the shifting profile. Numerous parameters such as the well deviation, the friction force of the shifter keys with the tubing, and the pull from the cable highly affect this downward force. Accurate positioning of the downhole tool with respect to the completion is even more challenging in deep water wells because the long cable stretch can result in several feet of uncertainty.
The novel method used in this operation consisted of using the shifter, linear actuator, and anchor modules to move in an inchworm motion after tagging the closed ball valve. The tag was used as a reference point to accurately locate the position of the shifter with respect to the valve opening shifting profile. While moving toward the profile, the position of the shifter was maintained at all times using the accurate linear position measurement of the tool. The linear actuator has a limited stroke, but it can be compounded to achieve a much longer measurement. Because the tag position of the shifter was only a few linear actuator strokes away from the opening profile, the operation was extremely efficient.
The intervention operation was successfully completed in a few hours using this method. The signals were measured downhole and reported in real time to surface, enabling accurate monitoring of the progress and indicating the position of the tool with respect to the valve opening profile at all times. While moving toward the profile after tagging the ball, the shifter was used to probe for diameter changes. This measurement provided an additional confirmation of the position of the shifter, which was able to sense passing through the profile. Finally, after passing the profile and reversing direction, a controlled increase in the linear actuator axial force confirmed the latch onto the opening profile. This seek method enabled latching onto the opening profile and confirmed without doubt that the shifter keys were engaged in the profile before proceeding to increase the forces to shift the ball open. While the ball valve was shifted open, the downhole measurements recorded an axial force vs. displacement footprint that is characteristic of the opening of the ball valve, giving confirmation that the operation was successfully completed without having to physically pass through the ball valve to confirm.
This was the first time that this method, consisting of moving in an inchworm motion after tagging the ball, had been used for locating and latching onto the shifting profile of a completion isolation valve. This novel method eliminated uncertainty from conventional methods that use the cable overpull and head tension as a latch indicator.