Solid Body Casing Mandrel Hanger for Single-Trip Locking
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Solution Overview
Problem
Traditional casing mandrel hangers require multiple trips to ensure proper locking and sealing, and elastomeric seals are prone to damage during installation, necessitating additional rig operations.
Innovation Solution
A single-piece solid body hanger with an inward biased lock ring and actuator system that allows for a single trip locking mechanism, utilizing a drive ring and ratchet mechanism to secure the hanger in a wellhead housing with a metal-to-metal seal, backed up by elastomeric seals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a traditional biased inward locking mechanism with single direction dogs is used, then rotational torque can be provided to land the hanger, but a single point of torque is not possible and two trips are required
Solution Approach 1:
The locking mechanism is segmented into two independent systems: an upper locking system with upper dogs that engage upper threads for rotational torque, and a lower locking system with lower dogs that engage lower threads for axial positioning. This segmentation allows each system to perform its specific function independently, enabling single-trip operation while maintaining manageable complexity through functional decomposition
Solution Approach 2:
The hanger body is designed with dual thread sets (upper and lower threads) that can engage with different running tools, making the hanger universally compatible with various installation methods. The single direction dogs are designed to function both as torque transmission elements during rotation and as locking elements during axial positioning, providing multi-functionality that reduces the number of trips required
2Reliability
If elastomeric isolation seals are used in traditional hangers, then sealing is provided, but the seals are prone to damage during installation requiring the complete string to be picked up
Solution Approach 1:
The seal assembly is designed with a protective boot that covers the elastomeric seals during installation. This boot acts as a cushioning protection that prevents damage to the seals before they are installed in their final position. The boot is removed only after the seals are properly seated, ensuring seal integrity is maintained throughout the installation process without requiring string retrieval
Solution Approach 2:
The seal assembly acts as an intermediary component between the hanger body and the casing string. It includes both elastomeric seals for primary sealing and a metal-to-metal seal as a backup sealing mechanism. This dual-sealing approach provides redundancy, ensuring that if one sealing mechanism fails, the other can maintain seal integrity, thereby improving reliability while simplifying repair operations
3Strength
If a solid body hanger design is used, then structural integrity is improved, but manufacturing complexity increases compared to traditional segmented hangers
Solution Approach 1:
While the hanger body is designed as a solid integrated structure for optimal strength, the locking mechanism is segmented into upper and lower components that can be manufactured separately and assembled. The upper dogs, lower dogs, and seal assembly are distinct components that attach to the solid hanger body. This approach maintains the structural integrity benefits of a solid body design while reducing manufacturing complexity through modular assembly of the locking components
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
Enables secure, single-trip installation and locking of the casing mandrel hanger with enhanced sealing capabilities, reducing operational complexity and minimizing seal damage.
Implementation Method 1
The actuator can include a drive ring threaded to the second set of threads. The drive ring can be wedged between the second set of threads and the inward biased lock ring to energize the lock ring by advancing along the second set of threads towards the second end surface.
Implementation Method 2
A set of ratchet teeth can extend radially around the shelf surface, configured to lock with a ratchet ring of a running tool for driving rotation of the solid body hanger in a first rotational direction and sliding relative to the solid body hanger in a second rotational direction opposite the first rotational direction.
Implementation Method 3
A casing with a landing surface can be engaged against the weight sealing surface as the metal-to-metal seal to prevent flow of fluids around the outward facing sealing surface in either up hole or down hole direction.
Implementation Method 4
Weight bearing in the down hole direction on the solid body hanger can bias the weight sealing surface toward the landing surface.
Data Source
AI summary
A running tool has a core and a sleeve rotatably engaged to the core with a first ratchet mechanism. A ratchet ring engaged inward of an inward surface of the sleeve is configured to form a second ratchet mechanism with a set of ratchet teeth of a solid body hanger. The solid body hanger is a single, solid piece. An inward biased lock ring is operatively connected to an actuator to energize outwardly to secure the solid body hanger in a wellhead housing. The solid body hanger includes a shoulder with a weight sealing surface configured to form a metal-to-metal seal with the solid hanger body landed out in a casing head housing A single trip downhole and back for the running tool can both land out the hanger and engage the lock ring.