Lock Ring Actuator for Radial Tubing Hanger Engagement
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Solution Overview
Problem
Conventional wellhead systems face challenges with tubing and casing hangers moving axially due to thermal expansion, leading to unreliable sealing and the need for multiple trips to install tubing hangers, which are time-consuming and costly.
Innovation Solution
A single-trip installation process for a tubing hanger system using a space-out mechanism with a ramp ring and piston that rigidizes the tubing and casing hangers within the wellhead housing, eliminating the need for a lead impression tool and ensuring secure sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional multi-trip installation process is used with lead impression tools, then measurement precision is improved, but loss of time and productivity are worsened
Solution Approach 1:
The tubing hanger is pre-adjusted at the surface before installation to establish the correct zero-gap connection geometry. This preliminary positioning eliminates the need for downhole measurement tools and multiple trips, as the hanger arrives already configured for proper installation.
Solution Approach 2:
A running tool with an indicator mechanism serves as an intermediary device that provides real-time visual feedback during installation. The indicator shows when the tubing hanger achieves the correct position relative to the locking profile, eliminating the need for lead impression tools while maintaining installation precision.
2Temperature
If thermal expansion forces are present in the wellhead system, then temperature is improved, but axial stability of hangers is worsened
Solution Approach 1:
The space-out mechanism is extracted as a separate, dedicated component between the tubing hanger and casing hanger. This isolated element specifically addresses thermal expansion by absorbing axial movements, protecting the seal assembly and locking mechanism from thermal-induced axial forces.
Solution Approach 2:
The space-out mechanism changes the axial distance parameter between the tubing hanger and casing hanger in response to thermal expansion. As temperature increases and the casing string expands upward, the space-out mechanism increases the axial gap, absorbing the expansion force and maintaining stable sealing contact.
3Reliability
If a zero-gap connection is required between tubing hanger and wellhead, then sealing reliability is improved, but device complexity is worsened
Solution Approach 1:
The tubing hanger incorporates self-aligning features including a tapered locking profile that automatically guides the hanger into the correct zero-gap position during installation. The running tool's indicator mechanism provides automatic visual confirmation of proper positioning, eliminating the need for complex measurement procedures or skilled judgment.
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 system provides time and cost savings by allowing a single-trip installation and enhances the rigidity of the wellhead system, preventing axial movement of the hangers and ensuring reliable sealing.
Implementation Method 1
The interface may include a tapered surface of the actuator and a matching tapered inner surface of the lock ring
Implementation Method 2
Actuating the actuator may include applying a compressive force with the flat surface to the lock ring to expand the lock ring radially outward
Data Source
AI summary
A hanger assembly includes: a main body; a lock ring coupled to the main body and configured to expand radially outward into a profile on an inner diameter of the wellhead; and an actuator, wherein the actuator is capable of transferring an axial force from the actuator into outward radial expansion of the lock ring toward the profile on the inner diameter of the wellhead. An interface between the actuator and the lock ring is shaped such that: axially downward movement of the actuator from a starting position to an intermediate position actuates the lock ring into the profile; and axially downward movement of the actuator from the intermediate position to a pre-load position applies a pre-load to the hanger assembly.