Wellhead Lock Screw Retention via Dual Gland Segmentation
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Solution Overview
Problem
Hydrocarbon extraction systems face challenges in securely suspending tubing and casing within wellheads, as existing systems lack effective mechanisms for redundant securing and easy removal of lock screws, leading to potential fluid leaks and contamination.
Innovation Solution
A wellhead tiedown system utilizing first and second glands to securely engage and retain lock screws, with the first gland blocking removal by engaging a flange and the second gland threadingly coupling to prevent axial movement without rotation, providing redundant retention and easy removal mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single locking mechanism is used for lock screws, then the device complexity is reduced, but the reliability of securing the hanger is insufficient
Solution Approach 1:
The locking mechanism is divided into two independent glands: a first gland with internal threads that engages external threads on the lock screw to prevent rotation, and a second gland with a flange that engages a flange on the lock screw to prevent axial movement. This segmentation provides redundant securing without requiring a single complex multi-functional component.
Solution Approach 2:
The first and second glands are positioned concentrically around the lock screw, with the first gland closer to the wellhead and the second gland further away. Both glands nest around the same lock screw body, creating a compact redundant locking system that secures the hanger through multiple engagement points.
2Reliability
If the lock screw is securely retained in the wellhead, then fluid leakage is prevented, but the ease of removal for maintenance is reduced
Solution Approach 1:
The retention mechanism is segmented into two independent glands that can be removed separately. The first gland prevents rotation while the second gland prevents axial movement. For maintenance, the glands can be independently accessed and removed, allowing the lock screw to be extracted without requiring complete disassembly of a single complex retaining structure.
Solution Approach 2:
The glands act as intermediary components between the lock screw and the wellhead body. They provide the securing function while being removable intermediaries that facilitate maintenance. The glands can be unscrewed and removed to allow access to and removal of the lock screw, then reinstalled to restore the secure locking state.
Data Source
AI summary
A system includes a wellhead tiedown system having a lock screw configured to move axially within an aperture of a spool. The wellhead tiedown system also has a first gland configured to couple to the spool within the aperture and block axial movement of the lock screw in a first direction, and a second gland configured to couple to the lock screw and block axial movement of the lock screw without rotation.