Hanger Sub Cable Support in Coiled Tubing
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Solution Overview
Problem
Existing methods for supporting cables within coiled tubing in downhole operations often fail to provide reliable and efficient weight distribution, leading to potential cable failure and movement issues, especially in high-pressure environments.
Innovation Solution
A method involving a hanger sub with an inner shoulder that extends radially into the coiled tubing string, allowing an elongate structural component, such as a metal capillary tube, to support the cable's weight by attaching an outer shoulder to the cable, ensuring it hangs securely below the hanger sub, which is positioned between 1% and 5% of the wellbore depth from the wellhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing cable support methods are used in coiled tubing, then cable installation is simple, but cable weight distribution is unreliable leading to cable failure and movement
Solution Approach 1:
The support system is segmented into multiple functional components: a hanger sub with shoulders for positioning, an elongate structural component (capillary tube) for weight support, and connection mechanisms. This segmentation allows each component to perform its specific function reliably while maintaining overall system manageability
Solution Approach 2:
The elongate structural component acts as an intermediary between the cable and the hanger sub, transferring the cable's weight to the hanger sub and coiled tubing. This intermediary structure provides reliable weight distribution without requiring direct complex anchoring of the cable to the coiled tubing
2Stability of the object's composition
If cable support structures are added to coiled tubing, then cable stability improves, but installation and removal of downhole tools becomes difficult
Solution Approach 1:
The hanger sub is designed to be movable within the coiled tubing during installation and removal operations. The shoulders provide stable positioning when needed, but the entire assembly can be dynamically repositioned or removed to facilitate downhole tool operations, then repositioned afterward
Solution Approach 2:
The hanger sub and cable support structure are installed in advance before downhole tool deployment. This preliminary installation ensures cable stability is established beforehand, while the design allows subsequent tool installation and removal without permanent obstruction
3Reliability
If traditional cable support methods are used, then installation is straightforward, but cable movement and failure occur in high-pressure environments
Solution Approach 1:
The hanger sub features radially extending shoulders that create a curved engagement surface within the coiled tubing. This curved geometry provides reliable mechanical engagement resistant to high-pressure forces while maintaining a compact profile that does not significantly obstruct the tubular interior
Solution Approach 2:
The support structure is nested within the coiled tubing interior, with the hanger sub positioned inside and the cable supported within the hanger sub structure. This nested arrangement provides robust support against pressure forces while maintaining ease of installation through sequential placement
Data Source
AI summary
A method of hanging a cable within a coiled tubing string includes the steps of determining a length of coiled tubing required within a well having a wellhead; determining a length of a cable required within the coiled tubing, the cable having a structural component along the length of the cable sufficient to support the weight of the cable; cutting the tubing string and installing a hanger sub in the coiled tubing string toward, the wellhead attachment section relative to the downhole end, the hanger sub comprising an inner shoulder that extends radially into the hanger sub and defines an opening; and attaching an outer shoulder to the cable and inserting the cable into the coiled tubing string until the outer shoulder of the cable engages the inner shoulder of the hanger sub such that the inner shoulder positions the cable below the outer shoulder.