Expandable Tubular Threadform With Enlarged Grooves for Post-Expansion Sealing
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Solution Overview
Problem
Expandable tubular connections in the oil and gas industry face challenges in maintaining connection strength, pressure rating, and torque rating after expansion, as the operational characteristics of the threads change, leading to potential weakness and reduced sealability.
Innovation Solution
Designing a threaded connection with enlarged grooves that provide clearance between flanks to accommodate the expansion of threads, ensuring a precise fit and maintaining performance criteria by allowing for radial expansion without deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional threadforms are used in expandable tubular connections, then the connection can be manufactured with standard thread dimensions, but the connection strength and sealability deteriorate after expansion due to thread deformation
Solution Approach 1:
The groove width is pre-enlarged during manufacturing before expansion occurs. This preliminary action creates sufficient clearance space that accommodates the thread deformation during expansion, preventing binding and maintaining connection integrity throughout the expansion process
Solution Approach 2:
The groove dimensional parameters are changed from standard dimensions to enlarged dimensions. Specifically, the groove width is increased to provide the necessary clearance for thread expansion, transforming the threadform geometry to accommodate radial expansion while maintaining connection strength and sealability
2Ease of manufacture
If standard groove dimensions are used, then the manufacturing process is simplified, but the threads cannot accommodate expansion without deformation
Solution Approach 1:
The groove width parameter is changed from standard to enlarged dimensions. This parameter modification maintains manufacturing simplicity while ensuring the groove can accommodate thread expansion without causing deformation or binding during the expansion process
3Strength
If clearance is provided between flanks for expansion, then thread deformation is prevented, but the connection geometry becomes more complex
Solution Approach 1:
The enlargement is applied locally only to the groove width parameter, while maintaining standard thread pitch, crest radius, and other critical threadform characteristics. This localized modification provides the necessary clearance for expansion without fundamentally changing the overall threadform geometry or complicating the connection design
Data Source
AI summary
A connection includes a first expandable tubular member having a first screw threadform defined by a first plurality of crests, roots, and flanks, where each flank separates each crest from each root. The connection also includes a second expandable tubular member having a second screw threadform defined by a second plurality of crests, roots, and flanks, where each flank separates each crest from each root. The crests and roots are substantially axial to the tubular members and the flanks are substantially radial to the tubular members. The first expandable tubular member and the second expandable tubular member are configured to connect when the first threadform engages with the second threadform. Clearances are formed between the first plurality of flanks and the second plurality of flanks when the first and second expandable tubular members connect.