Drill String Coupling Geometry for Bending Stress Relief
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional drill string couplings are prone to failure due to bending moments and wear, leading to reduced drilling efficiency and operational lifetime, particularly affecting the internally threaded ends.
Innovation Solution
A drilling component with a reduced cross-sectional area at one end to distribute stress and enhance resistance to bending moments, featuring a hollow interior with varying cross-sections to minimize stress concentrations and improve coupling durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional externally and internally threaded couplings are used to interconnect drill string sections, then the drill string can be assembled and function, but the coupling is subjected to bending forces that fatigue the threaded portion leading to breakage and reduced service life
Solution Approach 1:
The drilling component features a wall with non-uniform cross-sectional area, where the first cross-section area is smaller than the second cross-section area. This local variation in wall thickness creates a stress distribution optimization that reduces stress concentrations in the threaded portion while maintaining overall structural integrity and resistance to bending moments.
Solution Approach 2:
The patent modifies the geometric parameters of the drilling component by varying the wall cross-sectional area along its length. Specifically, the wall transitions from a smaller first cross-section area to a larger second cross-section area, creating a gradient structure that optimizes the component's mechanical properties for withstanding bending forces and reducing fatigue.
2Ease of manufacture
If uniform wall thickness is used in the drilling component, then manufacturing is simpler, but stress concentrations occur in the threaded portion under bending loads
Solution Approach 1:
The drilling component features a wall with non-uniform cross-sectional area, where the first cross-section area is smaller than the second cross-section area. This local variation in wall thickness creates a stress distribution optimization that reduces stress concentrations in the threaded portion while maintaining overall structural integrity and resistance to bending moments.
3Reliability
If the internally threaded end is used for coupling, then connection is achieved, but this end determines the operational lifetime due to increased wearing from stress transfer
Solution Approach 1:
The drilling component features a wall with non-uniform cross-sectional area, where the first cross-section area is smaller than the second cross-section area. This local variation in wall thickness creates a stress distribution optimization that reduces stress concentrations in the threaded portion while maintaining overall structural integrity and resistance to bending moments.
Data Source
Figure 1a~1b
Figure 1c~1d
Figure 2
AI summary
A drilling component (200) comprising a first end portion (260) configured to be arranged to face the a first section of a drill string, wherein the first end portion (260) comprises a first interconnecting portion (210) configured to engage a corresponding interconnecting portion of the first section of the drill string. The drilling (component 200) further comprises a hollow interior (230) configured to extend along a length direction (140) of the drill string and to form a part of a passage through the drill string. The drilling component (200) comprises a wall (220) defining the hollow interior (230), wherein an area of a first cross-section (240) of the wall (220) is smaller than an area of a second cross-section (250) of the wall (220) and wherein the first cross-section (240) is arranged between the second cross-section 240 and the first end portion (260).