Integrated Wear Bushing Lockdown for Wellhead Hanger Protection

Solution Overview

Problem

Existing wear bushing systems for wellhead assemblies do not effectively prevent damage to casing hangers from misalignment and eccentric rotation of drill strings during drilling operations, and require separate lockdown systems for thermal expansion management.

Innovation Solution

A wear bushing assembly that includes an annular sleeve and body with a lockdown ring and lock ring mechanism, which provides axial lockdown force and protects the casing hanger by transmitting forces through the wear bushing sleeve, and optionally includes pins and undulations for secure engagement with the wellhead housing, allowing for both protection and lockdown functionality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a wear bushing is landed axially above the casing hanger, then the drill tool will first contact the wear bushing and come into alignment with the casing hanger, protecting the casing hanger from damage, but the wear bushing requires separate lockdown systems to manage thermal expansion and provide axial lockdown force

Engineering Contradiction:

Improvedamage to casing hangerVSAvoidlockdown system

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent combines the wear bushing and lockdown hanger into a single integrated assembly. The wear bushing body includes an integrated lockdown ring that engages with the wellhead housing groove, merging the protection function and axial lockdown function into one component system. This eliminates the need for separate lockdown systems while maintaining both protective and locking capabilities.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The wear bushing assembly performs multiple functions simultaneously: it protects the casing hanger from misalignment and eccentric rotation damage, provides axial lockdown force to prevent thermal expansion movement, and enables drill tool alignment. The integrated design allows a single assembly to fulfill roles that previously required separate components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If a lockdown hanger is run separately to provide axial lockdown capability, then thermal expansion management is improved, but the overall system complexity increases and requires additional components

Engineering Contradiction:

Improvecasing lockdownVSAvoidnumber of components

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the wear bushing and lockdown hanger into a single integrated assembly. The wear bushing body includes an integrated lockdown ring that engages with the wellhead housing groove, merging the protection function and axial lockdown function into one component system. This eliminates the need for separate lockdown systems while maintaining both protective and locking capabilities.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The wear bushing assembly performs multiple functions simultaneously: it protects the casing hanger from misalignment and eccentric rotation damage, provides axial lockdown force to prevent thermal expansion movement, and enables drill tool alignment. The integrated design allows a single assembly to fulfill roles that previously required separate components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Object-affected harmful factors

If the drill string rotates eccentrically during drilling, then the drill string contacts and wears the wear bushing rather than the casing hanger, protecting the casing hanger, but the wear bushing may not provide sufficient axial lockdown force without additional lockdown mechanisms

Engineering Contradiction:

Improvewear on casing hangerVSAvoidaxial lockdown force

Core Design Contradiction:

Object-affected harmful factorsVSForce

Solution Approach 1:

The patent combines the wear bushing and lockdown hanger into a single integrated assembly. The wear bushing body includes an integrated lockdown ring that engages with the wellhead housing groove, merging the protection function and axial lockdown function into one component system. This eliminates the need for separate lockdown systems while maintaining both protective and locking capabilities.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS9476262B2Wear bushing with hanger lockdown

Publication Date: 2016.10.25 VETCO GRAY LLC

AI summary

A wear bushing assembly protects and locks down a hanger in a wellhead housing; and which includes a wear bushing body that inserts into a wear bushing sleeve. A lock ring extends into registered recesses on the body and sleeve to couple together the body and sleeve. The wellhead housing has a profiled recess circumscribing its inner surface. A lockdown ring selectively mates with the profiled recess; and when mated is in interfering contact with an upper surface of the wear bushing sleeve, thereby coupling the sleeve to the wellhead housing. The sleeve outer surface is profiled to interfere with upward movement of the hanger, so that force is transferred from the hanger to the housing through the sleeve which locks down the housing.