Drill Pipe Coupling Compressible Volume Radial Stiffness
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High-pressure drilling conditions lead to galling issues at the sealing surfaces of hydrocarbon well components due to high contact pressures, which existing solutions fail to address without compromising axial stiffness or increasing interference beyond machining tolerances.
Innovation Solution
A compressible volume, such as a recess or groove, is introduced in the terminal portion of the component to reduce radial stiffness by at least 20% while maintaining at least 60% of the axial stiffness, allowing for reduced galling and improved sealing under high pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high contact pressures are imposed at the sealing surfaces to ensure tightness under very high pressures, then sealing reliability is improved, but galling occurs due to excessive contact pressure and interference
Solution Approach 1:
The patent changes the physical state of the terminal portion by introducing a compressible volume, transforming it from a rigid structure to one with controlled compliance. This allows the sealing surface to deform elastically under pressure, distributing contact pressure more evenly and preventing galling while maintaining sealing reliability.
Solution Approach 2:
The compressible volume acts as a pre-designed cushioning element that absorbs excess contact pressure before it can cause galling. The elastic deformation of the terminal portion into the compressible volume provides a buffering effect that protects the sealing surfaces from harmful stress concentrations.
2Object-affected harmful factors
If interference is reduced to prevent galling, then galling risk is decreased, but sealing reliability deteriorates due to insufficient contact pressure
Solution Approach 1:
The patent introduces dynamic compliance to the sealing system through the compressible volume. The terminal portion can deform elastically in response to applied pressure, allowing the system to adapt to pressure variations while maintaining adequate contact pressure for sealing without requiring high initial interference.
Solution Approach 2:
The patent changes the mechanical properties of the terminal portion by adding the compressible volume, transforming it from a rigid component to one with controlled elasticity. This allows the system to achieve adequate sealing pressure through elastic deformation rather than relying solely on high interference fitting.
3Object-affected harmful factors
If radial stiffness is reduced to decrease galling, then contact pressure distribution improves, but axial stiffness may be compromised affecting make-up torque
Solution Approach 1:
The patent applies local quality modification by introducing the compressible volume only in specific regions of the terminal portion, typically away from the central axis. This creates localized compliance in the radial direction to reduce galling while preserving axial stiffness in the load-bearing path through the center of the component.
Solution Approach 2:
The patent addresses the stiffness contradiction by operating in different dimensional directions. The compressible volume provides compliance primarily in the radial direction (perpendicular to the axis) while maintaining stiffness in the axial direction (parallel to the axis), effectively decoupling the stiffness requirements in different dimensions.
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 solution effectively reduces galling and maintains sufficient axial stiffness, enabling higher radial interference and improved sealing without compromising the make-up torque or increasing instability, thus optimizing the seal under high-pressure conditions.
Implementation Method 1
a compressible volume is provided in the thickness of the first terminal portion and partially beneath the sealing surface, in order to reduce the radial stiffness of said terminal portion by at least 20%, while conserving at least 60% of the axial stiffness
Data Source
AI summary
A component used for drilling and operating hydrocarbon wells which is substantially tubular in form, and including a first end configured to be connected to a second end of another component also used for drilling and operating hydrocarbon wells. The first end includes a terminal portion including a first abutment surface configured to cooperate by interference with a corresponding abutment surface on the second end, and including a sealing surface configured to cooperate by interference with a corresponding sealing surface on the second end, the terminal portion being preceded by a threaded zone configured to be made up into a corresponding threaded zone of the second end. A compressible volume is provided in the thickness of the first terminal portion and partially beneath the sealing surface, to reduce radial stiffness of the terminal portion by at least 20%, while conserving at least 60% of axial stiffness.