Multiple-Tapered Drill String Connections for Fast Threading
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Solution Overview
Problem
Existing threaded connections in drill string components face challenges in handling and threading due to low taper designs, leading to increased time and thread damage during assembly, and poor torsional capability and reliability.
Innovation Solution
A multiple tapered threaded connection design with varying tapers, including a first taper of 0.75 inches per foot and a second taper of 2 inches per foot, along with transitional threads to facilitate quick assembly and reduce thread damage, while maintaining mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a low taper design (0.50 to 1.00 inches per foot) is used to maximize torsional capability, then torsional strength is improved, but threading time and thread damage increase significantly
Solution Approach 1:
The threaded connection is divided into multiple sections with different tapers: a first section with a first taper (0.75 inches per foot) and a second section with a second taper (2.00 inches per foot). This segmentation allows each section to serve different functions - the first section provides torsional strength while the second section enables quick stabbing and reduces threading time
Solution Approach 2:
Different portions of the threaded connection have different local properties - the first portion has a gentler taper optimized for torque bearing, while the second portion has a steeper taper optimized for rapid engagement. This local differentiation resolves the contradiction by optimizing each region for its specific function rather than using a uniform taper throughout
2Strength
If a low taper design is used, then torsional capability is improved, but the number of revolutions required for full engagement increases
Solution Approach 1:
The connection is segmented into two taper sections where the second section with steeper taper (2.00 inches per foot) specifically addresses the productivity issue by reducing the number of revolutions needed for initial engagement, while the first section maintains torsional capability
Solution Approach 2:
The taper parameter is changed along the length of the connection - transitioning from a gentler taper (0.75 inches per foot) in the first section to a steeper taper (2.00 inches per foot) in the second section. This parameter variation allows the connection to achieve both high torsional capability and fast assembly speed
3Ease of manufacture
If a single taper design is used, then manufacturing is simpler, but mechanical strength and stress distribution are insufficient
Solution Approach 1:
Rather than using a single uniform taper, the connection is segmented into multiple sections with different tapers. This segmentation improves mechanical strength and stress distribution by optimizing each section for specific load conditions, while still maintaining reasonable manufacturing complexity through the use of standard machining processes
4Force
If a low taper design is used, then torque bearing capacity is improved, but handling and threading difficulty increase
Solution Approach 1:
The connection is segmented into two functional sections: the first section with gentler taper optimizes torque bearing capacity, while the second section with steeper taper optimizes handling ease by enabling quick stabbing and reduced threading effort. This segmentation resolves the contradiction between torque capacity and handling ease
Data Source
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AI summary
A threaded connection between adjacent drill string components comprises a threaded female connection end adapted to receive a correspondingly threaded male connection end, the two ends each having first and second portions of different tapers. Tubular members, drill string tools and other drill string components comprising the female or male ends described herein are also provided.