Anchor Slip Seal Locking Mechanism for Liner Hanger
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Solution Overview
Problem
The existing methods for testing cement integrity using a packer on a liner hanger often overstress the liner due to differential pressure load being transferred to the seal, which can lead to damage, and the mechanical operation with drag blocks prevents subsequent string manipulation.
Innovation Solution
A test packer is hydraulically unlocked to extend slips and set the packer seal during running in, allowing differential pressure load to be absorbed by the slips, not the liner hanger seal, and then locked in place for subsequent rotation and fluid circulation without using drag blocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a packer is set on a liner hanger to test cement integrity, then the cement integrity test can be performed, but the differential pressure load overstresses the liner hanger seal and potential damage to the liner
Solution Approach 1:
The packer slips act as an intermediary load-bearing element between the packer seal and the liner hanger seal. When the packer is set, the slips engage with the casing to support the differential pressure load, preventing this load from being transferred to the liner hanger seal and thus protecting the liner from overstress while still enabling the cement integrity test
Solution Approach 2:
The patent replaces the traditional mechanical drag block system with a hydraulic locking mechanism. The packer is initially held retracted by a hydraulic lock that prevents the slips and seal from setting during run-in. After positioning, hydraulic pressure is released to allow the slips to set and engage the casing, substituting hydraulic control for mechanical drag blocks
2Stability of the object's composition
If drag blocks are used to prevent packer movement, then the packer can be held in position, but subsequent string rotation and reciprocation are prevented due to drag block rubbing against the casing wall
Solution Approach 1:
The packer system transitions from a static held position to a dynamic set position through hydraulic control. Initially, the hydraulic lock keeps the packer retracted and the slips disengaged, allowing free string manipulation. When needed, the hydraulic lock releases and the slips dynamically engage with the casing to hold the packer in the set position, eliminating the need for drag blocks that would prevent subsequent rotation
Solution Approach 2:
The patent extracts and eliminates the drag block component from the system entirely, replacing its function with a combination of hydraulic locking and slip engagement. This removal of the drag block eliminates the rubbing against the casing wall that would prevent string rotation and reciprocation during subsequent operations
3Reliability
If the packer is extended to set the seal and slips, then the differential pressure load is absorbed by the slips, but the packer cannot be retracted for subsequent operations without a locking mechanism
Solution Approach 1:
The patent replaces complex mechanical locking mechanisms with a simpler hydraulic locking system. A hydraulic lock holds the packer in the retracted position during run-in by preventing the slips from extending. When the packer needs to be set, the hydraulic pressure is released, allowing the slips to extend and engage the casing under differential pressure. For subsequent operations, a ball-drop mechanism breaks a shear restraint, allowing a spring to automatically return the packer to the retracted position, providing a simple and reliable locking system
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 prevents overstressing of the liner hanger and enables subsequent operations like rotation and fluid circulation without damaging the casing, ensuring the integrity of the liner hanger during cement testing.
Implementation Method 1
A first ball is dropped to shift a sleeve to release the grip of dogs to a groove on an outer housing
Implementation Method 2
Setting down weight sets the test packer seal and sets the slips
Implementation Method 3
A second ball lands on the same seat now enlarged due to earlier movement and breaks a retainer on a locking sleeve
Implementation Method 4
A spring return or continued downhole motion of the locking sleeve locks the packer in the run in position
Implementation Method 5
the differential pressure load is not applied to the seal in the liner hanger
Data Source
AI summary
A test packer is lowered to a set liner hanger in a locked position that prevents the seal and slips from setting during running in. A first ball is dropped to shift a sleeve to release the grip of dogs to a groove on an outer housing. Setting down weight sets the test packer seal and sets the slips. After the casing integrity pressure test is done the test packer is lifted to again position the groove in the outer housing by the dogs. A second ball lands on the same seat now enlarged due to earlier movement and breaks a retainer on a locking sleeve. A spring return or continued downhole motion of the locking sleeve locks the packer in the run in position. Subsequent rotation and circulation can take place as completion fluid is circulated in. A circulation port above the packer can be opened optionally for circulation or reversing above the test packer.