Anchor Assembly with Balance Piston for Deep Well Liners
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Solution Overview
Problem
Existing methods for installing liners in oil and gas wells face challenges such as mechanical hangers getting stuck, requiring separate packers for sealing, and limitations in load capacity due to the use of ductile metals, which are prone to relaxation and increased installation costs in deep wells under extreme conditions.
Innovation Solution
The development of anchor assemblies comprising a nondeformable mandrel, an expandable metal sleeve, and a swage that radially expands to contact the existing conduit, along with novel clutch mechanisms and hydraulic actuators with a balance piston to enhance load capacity and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical hangers with ductile metal slips are used to install liners, then the liner can be supported in the casing, but the hanger may get stuck during installation and requires separate packers for sealing
Solution Approach 1:
The patent extracts the sealing function from the mechanical hanger assembly by using a separate packer that is set independently. The mechanical hanger uses a simple slip mechanism without integrated sealing elements, allowing the hanger to be installed and then sealed separately with a packer that is set by circulating fluid to expand against the casing wall.
Solution Approach 2:
The installation process is segmented into distinct operations: first installing the mechanical hanger with slips, then separately setting the packer. This segmentation allows each component to be optimized independently - the hanger for mechanical support and the packer for sealing - while simplifying the overall installation procedure.
2Ease of operation
If ductile metals are used in mechanical hangers to allow deformation, then the hanger can expand to grip the casing, but the metal relaxes over time reducing load capacity
Solution Approach 1:
The patent employs a dynamic setting mechanism where a punch tool is driven axially to compress and set the packer in place. This dynamic compression process creates a permanent set in the packer material, allowing it to maintain constant sealing pressure against the casing wall without the relaxation problems of ductile metal expansion.
Solution Approach 2:
The patent changes the material parameter from ductile metal (which relaxes) to a packer material that can be permanently deformed by compression. The packer is compressed by a punch tool to a final set state where it maintains constant sealing force, eliminating the time-dependent relaxation behavior of elastic metal expansion.
3Power
If conventional hydraulic actuators are used without pressure balancing, then the actuator can generate force, but pressure imbalances cause deformation and reduced reliability in deep wells
Solution Approach 1:
The patent incorporates a balance piston that provides feedback on pressure imbalances between the actuator chambers and the wellbore environment. This balance piston senses pressure differences and adjusts the actuator's internal pressure distribution to maintain equilibrium, preventing deformation and ensuring reliable operation in deep well conditions.
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 anchor assemblies achieve higher load capacities with reduced force requirements, minimize the need for separate packers, and provide a reliable seal while resisting deformation and corrosion, thus enabling efficient and cost-effective liner installation in deep wells.
Implementation Method 1
The swage is supported for axial movement across the outer surface of the mandrel from a first position axially proximate to the sleeve to a second position under the sleeve. The movement of the swage from the first position to the second position expands the sleeve radially outward into contact with the existing conduit.
Implementation Method 2
The balance piston is slidably supported within the top hydraulic chamber of the actuator, preferably on the mandrel. The balance piston includes a passageway extending axially through the balance piston. Fluid communication through the piston and between its upper and lower sides is controlled by a normally shut valve in the passageway.
Data Source
AI summary
Anchor assemblies for installation within an existing conduit. The anchor assemblies have a nondeformable mandrel, an expandable metal sleeve, and a swage. The expandable metal sleeve is carried on the outer surface of the mandrel. The swage is supported for axial movement across the mandrel outer surface from a first position axially proximate to the sleeve to a second position under the sleeve. The movement of the swage from the first position to the second position expands the sleeve radially outward into contact with the existing conduit.