Liner Hanger Slip Actuation via Moveable Cover
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Solution Overview
Problem
Existing oil and gas well liner hanger designs face limitations in pressure rating, flexibility, and usable diameter due to full circumference hydraulic pistons and complex seal systems, leading to reduced maximum working pressure and increased outer diameter, which restricts the size of the liner that can be used within the casing.
Innovation Solution
A coupler with an enlarged inner diameter pocket containing a slip initially restricted by a moveable cover, actuated by an inner tubing's actuator to set the slip within the casing, allowing for a larger diameter liner to be used while maintaining a smaller outer diameter, thus preserving usable cross-sectional area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If full circumference hydraulic pistons are used to actuate slips, then the slips can be set, but the pressure rating is limited to approximately 3,000 PSI while the mandrel is rated for 12,000 PSI
Solution Approach 1:
The patent removes the cylindrical piston housing assembly entirely and replaces it with a simpler mechanism where slips are actuated by a conical surface that translates axial movement into radial expansion. This extraction eliminates the pressure rating limitation imposed by the piston housing while maintaining the ability to set slips effectively.
Solution Approach 2:
Instead of using a piston to push slips radially outward, the patent inverts the mechanism by using a conical surface where axial translation of the slip assembly automatically camming the slips radially outward through the cone geometry. This inversion eliminates the need for a pressure-limited piston housing.
2Reliability
If liner hanger setting components are placed on the outside of the liner, then the liner can be secured within the casing, but the overall outer diameter increases reducing usable diameter
Solution Approach 1:
The patent nests the slip assembly and setting mechanism within the inner diameter of the liner itself, rather than placing components on the outer surface. The slips are positioned inside the liner and expand outward to engage the casing, effectively utilizing the annular space between liner and casing for the setting mechanism, thereby preserving the outer diameter.
Solution Approach 2:
The patent moves the setting components from the radial outer dimension to the axial dimension by using a conical surface that converts axial movement into radial expansion. This dimensional transformation allows the mechanism to fit within the liner's inner diameter while achieving the same securing function.
3Strength
If multiple pistons with seals are used to actuate slips, then higher pressure rating is achieved, but manufacturing cost increases and leak paths increase
Solution Approach 1:
The patent removes multiple pistons and their associated seals from the design, replacing them with a single conical surface mechanism. This extraction eliminates the complex manufacturing requirements and multiple potential leak paths while maintaining the pressure rating through the simplified geometry.
Solution Approach 2:
The patent replaces expensive sealed piston assemblies with a simpler, seal-free conical mechanism that has fewer moving parts and no seal requirements, significantly reducing manufacturing cost and eliminating leak paths while maintaining functional effectiveness.
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 design enhances the pressure rating and flexibility of the liner hanger system, enabling a larger diameter liner to be used within the casing, improving fluid flow and tool passage while minimizing the overall outer diameter of the liner hanger, thus increasing the usable diameter of the well.
Implementation Method 1
As the slips are translated axially, they are cammed radially outward by a ramped surface that is fashioned into the mandrel. As the slips move radially outward, the toothed surfaces of the slip will bitingly engage the inner wall surface of the wellbore casing.
Implementation Method 2
Actuation systems for such slips in the past employed full circumference hydraulically actuated pistons to move the slips.
Data Source
AI summary
A liner hanger has a housing with a pocket disposed on an inner wall surface and a slip slidingly engaged within the pocket. A moveable cover is disposed interior to the slip thereby restricting movement of the slip from a unset position to a set position. The liner hanger housing is secured in the string of casing and an actuator is mounted on the liner. As the liner is moved through the casing coupler, the actuator actuates the cover, causing the cover to be moved so that the slip can move axially downward from its unset position to its set position. As the cover is moved, the slip moves radially inward and grips the liner to secure the liner within the casing string of the wellbore.