Downhole Release Apparatus Blocking Member Mechanism
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Solution Overview
Problem
Downhole tools and equipment often become stuck in wellbores, and existing release mechanisms, such as shear pins, limit the upward jarring force that can be applied and are prone to wear, making it difficult to free stuck tool strings effectively.
Innovation Solution
A downhole tool with a release mechanism comprising a housing, latching members, and a blocking member that moves from a position preventing disengagement to one allowing disengagement, enabling the separation of tool string portions, facilitated by relative movement between the housing and latching members, including upward and downward jarring actions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If shear pins are used as release mechanism, then tool string separation is enabled, but upward jarring force is limited by the breaking force limit of the shear pin
Solution Approach 1:
The release mechanism is divided into separate functional components: a blocking member that can be moved to allow latching member disengagement, and a latching member that engages with a corresponding member to secure the tool string. This segmentation allows the blocking member to be actuated by impacts below the shear pin breaking force, enabling controlled release without being limited by the shear pin's breaking force threshold.
Solution Approach 2:
The blocking member acts as an intermediary between the impact force and the latching member. By moving the blocking member to a position that allows disengagement, the system enables release through intermediate blocking member movement rather than directly breaking the shear pin, thus overcoming the force limitation.
2Productivity
If shear pins are used as release mechanism, then tool string separation is enabled, but wear and fatigue limit the number of impacts that can be applied
Solution Approach 1:
The release mechanism is divided into separate functional components: a blocking member that can be moved to allow latching member disengagement, and a latching member that engages with a corresponding member to secure the tool string. This segmentation allows the blocking member to be actuated by impacts below the shear pin breaking force, enabling controlled release without being limited by the shear pin's breaking force threshold.
Solution Approach 2:
The system changes the operational parameter from breaking the shear pin to moving the blocking member. By designing the blocking member to move at lower impact forces, the system enables repeated impacts without the wear and fatigue that would occur with repeated shear pin breaking attempts, thus increasing the number of usable impacts.
3Ease of operation
If impact tool is used to dislodge stuck tool string, then tool string may be freed, but impact force is limited by shear pin breaking force
Solution Approach 1:
The blocking member acts as an intermediary between the impact force and the latching member. By moving the blocking member to a position that allows disengagement, the system enables release through intermediate blocking member movement rather than directly breaking the shear pin, thus overcoming the force limitation.
Solution Approach 2:
The blocking member is designed to be movable between positions that block and allow latching member disengagement. This dynamic positioning capability enables the system to respond to impact forces and transition to a releasable state without requiring forces high enough to break the shear pin, thus improving ease of operation.
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
This solution allows for increased upward jarring force without breaking shear pins, reducing wear and enabling repeated impacts to free stuck tool strings, improving the efficiency of tool string retrieval and reducing the risk of equipment damage.
Implementation Method 1
the first and second latching members engage thereby connecting the first and second connector subs
Implementation Method 2
the blocking member is movable from a first position in which the blocking member prevents the first and second latching members from disengaging to a second position in which the blocking member permits the first and second latching members to disengage
Implementation Method 3
relative movement between the housing and first latching member facilitates movement of the blocking member from the first position to the second position
Data Source
Figure 1
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Figure 3
AI summary
A downhole release apparatus (200) having a first connector sub (202) connectable with a first portion (112) of a tool string and a second connector sub (204) connectable with a second portion of the tool string (114). The first connector sub (202) may include a housing (203), a first latching member (222), and a blocking member (226). The second connector sub may include a second latching member (224). The first and second latching members (222, 224) may engage thereby connecting the first and second connector subs (202, 204). The blocking member (226) may be movable from a first position in which the blocking member prevents the first and second latching members from disengaging to a second position in which the blocking member permits the first and second latching members to disengage thereby permitting the first and second connector subs to disconnect. Relative movement between the housing and first latching member may facilitate movement of the blocking member from the first position to the second position.