Premium Threaded Connection Conversion for HPHT Tubulars
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Solution Overview
Problem
Existing threaded connections for oil and gas tubulars, such as NC46 connections, are inadequate for high-pressure and high-temperature applications like horizontal drilling and hydraulic fracturing, necessitating the development of premium threaded connectors that can withstand extreme conditions.
Innovation Solution
The method involves converting NC46 connections to CET43 connections by reducing and enlarging the outer and inner diameters of tubular components, applying CET43 threads, and optionally heating the hardband portion and phosphating the connections, to create a high-performance threaded system with enhanced torsional strength and torque capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If NC46 threaded connections are used in tubulars, then the tubulars can be manufactured with standard specifications, but the connections cannot withstand high-pressure and high-temperature conditions in demanding applications
Solution Approach 1:
The patent transforms standard NC46 connections into premium CET43 connections by modifying geometric parameters including thread profile, pitch, diameter, and taper angle. These parameter changes enable the connection to withstand high-pressure and high-temperature conditions while maintaining compatibility with existing tubular dimensions
2Strength
If premium CET43 threaded connections are applied to convert existing NC46 tubulars, then torsional strength increases by 170-200%, but the manufacturing process complexity increases
Solution Approach 1:
The patent employs preliminary machining operations including heating the hardband portion to soften it, reducing outer diameter, enlarging inner diameter, and preparing the connection geometry before applying the CET43 thread profile. This preliminary preparation simplifies the overall transformation process by creating optimal conditions for thread application
Solution Approach 2:
The manufacturing process modifies multiple parameters systematically: heating temperature, diameters, thread pitch, and profile geometry. These coordinated parameter changes achieve the strength enhancement while maintaining a systematic and manageable manufacturing workflow
3Ease of manufacture
If the hardband portion is heated to softening temperature for diameter reduction, then the material becomes more workable, but energy consumption increases
Solution Approach 1:
The patent utilizes thermal heating to expand and soften the hardband portion material, making it more ductile and easier to machine for diameter reduction. The localized heating approach minimizes energy consumption by treating only the specific region requiring modification
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 CET43 connections provide 170-200% torsional strength of API connections, enabling reliable performance in demanding applications like horizontal drilling and hydraulic fracturing, with improved torque and reduced shoulder and nose length, while allowing for recutting and reuse of tubulars.
Implementation Method 1
heating the hardband portion to a softening temperature
Data Source
AI summary
A method of converting a tubular having NC46 connections to CET®43 connections. A method of applying a CET®43 thread to a pin connection or a box connection or both. A box connection and a pin connection of the tubular are machined and a CET®43 thread applied to the box connection and the pin connection.