Riser Tubular Groove Cladding for Threaded Connection Strength

Solution Overview

Problem

Existing riser assemblies for offshore drilling require a separate upset forging process to increase box end diameters for threading, which is inefficient and may not provide optimal material for machining threads, and the connection between tubulars can be unreliable due to lack of surface profile for metal cladding adhesion.

Innovation Solution

A method of forming grooves on the ends of tubulars with metal cladding applied over these grooves, and threads on both inner and outer surfaces to create a secure connection between pin and box ends, allowing for interlocking without the need for coaxial unions or upset forging, using a metal spray process that can include machining cuttings for enhanced adhesion and strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If a separate upset forging process is used to increase box end diameters for threading, then the diameter is increased to provide material for machining threads, but the process becomes more complex and inefficient

Engineering Contradiction:

Improvebox end diameterVSAvoidprocess complexity

Core Design Contradiction:

ShapeVSDevice complexity

Solution Approach 1:

The patent combines the groove formation and metal cladding application into a single integrated process. The grooves are formed on the tubular ends, and metal cladding is applied directly over these grooves in the same operational sequence, eliminating the need for separate upset forging processes and reducing overall process complexity while achieving the required dimensional characteristics for threading.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The grooves are formed on the tubular ends before the metal cladding is applied. This preliminary groove formation creates the necessary surface profile that enhances subsequent cladding adhesion, allowing the threading process to proceed efficiently without requiring additional upset forging operations to increase diameter.

Inventive Principle:

Principle #10Preliminary action

2Strength

If metal cladding is applied without surface profile preparation, then the application process is simpler, but adhesion and strength of connection are reduced

Engineering Contradiction:

Improvecladding adhesionVSAvoidmanufacturing simplicity

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The patent applies metal cladding specifically over the grooved regions of the tubular ends. The grooves create localized surface profiles that enhance adhesion properties in these critical areas, ensuring strong connection strength where it is most needed for the threaded assembly while maintaining manufacturing efficiency.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The grooves are formed on the tubular ends before the metal cladding is applied. This preliminary groove formation creates the necessary surface profile that enhances subsequent cladding adhesion, allowing the threading process to proceed efficiently without requiring additional upset forging operations to increase diameter.

Inventive Principle:

Principle #10Preliminary action

3Strength

If grooves are formed on tubular ends before cladding, then adhesion and strength are improved, but the manufacturing process becomes more complex

Engineering Contradiction:

Improveconnection strengthVSAvoidprocess complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The patent combines the groove formation and metal cladding application into a single integrated process. The grooves are formed on the tubular ends, and metal cladding is applied directly over these grooves in the same operational sequence, eliminating the need for separate upset forging processes and reducing overall process complexity while achieving the required dimensional characteristics for threading.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent applies metal cladding specifically over the grooved regions of the tubular ends. The grooves create localized surface profiles that enhance adhesion properties in these critical areas, ensuring strong connection strength where it is most needed for the threaded assembly while maintaining manufacturing efficiency.

Inventive Principle:

Principle #3Local quality

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

This method enables secure and efficient assembly of tubulars with improved adhesion and strength of connections, reducing material waste and operational complexity while maintaining consistent diameters, enhancing the reliability and efficiency of riser assemblies in offshore drilling operations.

Implementation Method 1

depositing a layer of metal cladding onto the end portions of the tubulars and over the grooves

Methodology Applied

Scientific EffectMetal spray deposition: Plasma Spray

Data Source

PatentUS9057226B2Method of forming a machinable surface

Publication Date: 2015.06.16 VETCO GRAY LLC

AI summary

A riser assembly and method of forming where the riser assembly is made up of tubular members joined together. A metal spray process applies a layer of cladding onto ends of the tubular members and the ends are threaded to form respective box and pin configurations. Grooves are provided onto the surface of the tubular members beneath where the metal spray is applied for enhancing adhesion of the cladding and tubular members. The layer of cladding provides sufficient material so that threads may be selectively formed on the outer or the inner surface of the tubular members.