Keyed Tangential Slip System for Retrievable Drilling Tools
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Solution Overview
Problem
Existing slip systems in the drilling and completion industry face difficulties in retrievability due to sticking issues in tubular structures and inadequate holding strength, particularly with conical configurations and tangentially loaded systems.
Innovation Solution
A keyed slip system with a sliding rod mechanism and tapered profiles allows for radial expansion and easy retrieval by axially moving end rings, reducing the force required for unsetting and facilitating tangential loading without conical structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conical structures are used to impart radially outwardly directed impetus on slips, then holding strength is improved, but retrievability deteriorates due to sticking in tubular structures
Solution Approach 1:
The slip system transitions from a static conical configuration to a dynamic tangentially loaded configuration where slips can be actively moved along the tubular structure. The key mechanism allows the slip to be loaded tangentially and then retrieved by applying axial force, enabling the system to dynamically change state between set and unset positions without sticking.
Solution Approach 2:
The conical structure that causes sticking is removed from the system. Instead, a separate key component is introduced that can be independently moved within the slip body, allowing the gripping function to be separated from the expansion mechanism, thereby eliminating the sticking problem while maintaining holding strength.
2Ease of operation
If tangential loading is used to avoid conical portions, then retrievability is improved, but holding strength becomes inadequate
Solution Approach 1:
A key component acts as an intermediary between the axial retrieval force and the radial expansion force. When axial force is applied to the key, it converts this force into tangential loading on the slip body through friction and geometric interaction, enabling the slip to be retrieved without requiring direct radial expansion.
Solution Approach 2:
The system changes the loading parameters from direct radial expansion to tangential loading. By applying axial force to the key, the system transforms the force vector and loading mode, allowing the slip to be unset by changing the applied force parameters rather than directly opposing the radial expansion force.
3Strength
If slips are made to radially expand for greater engagement, then holding strength is improved, but force required for retrieval increases
Solution Approach 1:
The key serves as a mechanical intermediary that decouples the retrieval force from the holding force. By applying axial force to the key rather than directly to the slip body, the system uses the key as a lever arm and friction interface to amplify the retrieval force, reducing the direct force required to unset the slip while maintaining strong holding engagement.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The keyed slip system enhances retrievability by reducing the force needed for unsetting and maintaining holding strength, improving the ease of retrieval of equipment from tubular structures.
Implementation Method 1
at least one sliding rod supporting slidable movement of the key within the frame
Implementation Method 2
The first portion of the key and the interior of the frame may each have tapered profiles
Data Source
Figure 1
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Figure 3
AI summary
A slip for a tangentially loaded retrievable slip system. The slip includes a frame including an interior having first and second sides; and, a key having a first portion within the interior of the frame. The first portion having first and second sides. The first portion of the key movable within the interior of the frame; wherein the key is movable from a set condition with at least a contact point of the first and second sides of the first portion of the key pushing against at least a portion of the first and second sides of the interior of the frame in the set condition. Respectively, to an unset condition with the first and second sides of the first portion of the key releasing pressure from the first and second sides of the interior of the frame. Also included is a method of managing a tangential load imparted by a tangential slip system.