Double Grip Packer Release Assist for High-Pressure Slip Release
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Solution Overview
Problem
Existing double grip downhole packers face difficulties in relaxing and decompressing the packing element under high downhole pressure conditions, making it challenging to release the slips and retrieve the packer from the well.
Innovation Solution
A release assist assembly comprising a mandrel, outer dog housing, slip cone structure, dog release sleeve, and inner release assist snap ring, which allows the packing element to be relaxed and decompressed, enabling the slips to be released for mechanical retrieval.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the packing element is compressed to seal against the casing under high pressure, then the sealing effectiveness is improved, but the stored energy in the compressed packing element increases, making it difficult to relax and decompress the packing element to release the slips
Solution Approach 1:
The release assembly is divided into multiple functional components including a release tool, release bridge, and dog elements that can independently move and interact. This segmentation allows the system to manage the complex task of releasing slips under high pressure by breaking it into manageable steps: engaging the release tool, actuating the release bridge, and disengaging the dog elements from the slips.
Solution Approach 2:
The release bridge acts as an intermediary component between the release tool and the dog elements. It receives force from the release tool and translates it into motion that disengages the dog elements from the slips. This intermediary mechanism allows the system to overcome the high stored energy in the compressed packing element by providing a mechanical advantage and controlled force transmission path.
2Strength
If the packing element is compressed to hold the packer in position, then the holding strength is improved, but the force required to decompress the packing element and release the slips increases
Solution Approach 1:
The release mechanism utilizes dynamic motion to overcome the static holding force. The release bridge moves from an initial position to a released position, converting rotational or linear motion into the force needed to disengage the dog elements. This dynamic approach allows the system to overcome the high holding strength of the compressed packing element by applying force over a distance and time, rather than requiring a single large force impulse.
Solution Approach 2:
The release mechanism introduces a new dimension of motion perpendicular to the axis of the compressed packing element. By moving the release bridge laterally or rotationally, the system can disengage the dog elements from the slips without directly opposing the axial compression force. This dimensional change allows the release mechanism to bypass the high force requirement by exploiting a different degree of freedom.
3Reliability
If the dog elements are extended into the dog housing to engage the slips, then the engagement reliability is improved, but the complexity of the release mechanism increases
Solution Approach 1:
The release bridge serves multiple functions: it acts as a force transmission element, a motion converter, and a positioning mechanism for the dog elements. This multi-functionality reduces the need for separate components and simplifies the overall release mechanism while maintaining reliable engagement. The same component that transmits force also controls the positioning and disengagement of the dog elements from the slips.
Solution Approach 2:
The release mechanism merges the functions of force application, motion control, and dog element disengagement into a single integrated assembly. The release tool, release bridge, and dog elements work together as a unified system where the motion of one component directly causes the desired action in another. This merging reduces the number of separate mechanisms needed and simplifies the overall device complexity while maintaining engagement reliability.
Data Source
AI summary
A release assist assembly and method for downhole tools, and a double grip packer having the release assist assembly installed therein wherein the release assist assembly operates under high downhole pressure conditions to relax and decompress the packing element of the packer to allow the slips of the packer to be released for mechanically retrieving the packer from the well.