Threaded Multilateral Junction for Maximum Main Bore Diameter
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Solution Overview
Problem
The oil and gas industry faces challenges in creating a low-cost, NACE-approved multibranch inflow control junction with a maximum internal diameter for hydrocarbon reservoirs, while maintaining structural integrity and avoiding a reduction in the main bore's internal diameter, particularly in formations with high subsidence pressures.
Innovation Solution
A multilateral junction design using a y-block with integrated main and lateral bores, threaded interfaces, and round-shaped lateral legs, allowing for the use of low-cost, corrosion-resistant alloys, eliminating the need for welding, and ensuring compliance with ANSI/NACE MR0175 standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the lateral bore is manufactured to have a D-shape to maximize main bore internal diameter, then the main bore internal diameter is increased, but the compression rating and collapse rating of the lateral leg decrease
Solution Approach 1:
The patent employs asymmetric geometry by using a D-shaped lateral bore opening that receives a round lateral leg. The D-shaped bore provides maximum internal diameter for the main bore while the round lateral leg maintains structural strength. This asymmetric configuration allows the main bore to have enlarged diameter without compromising lateral leg integrity, as the round shape of the lateral leg resists collapse pressure more effectively than a D-shaped leg would.
2Strength
If welded junctions are used to connect lateral legs to main bore, then structural integrity is achieved, but material hardness must be less than 250 HV for NACE approval, limiting material selection
Solution Approach 1:
The patent replaces the welding process with a mechanical threading system. Instead of welding lateral legs to the main bore, the invention uses threaded connections where lateral legs are screwed into the lateral bore. This substitution eliminates the need to control material hardness at 250 HV or below, allowing use of stronger, more versatile materials that would be unsuitable for welding but are perfectly suitable for threading operations.
3Strength
If high-strength materials are used to improve collapse rating, then structural integrity improves, but cost increases and NACE approval becomes difficult
Solution Approach 1:
By replacing welding with threading, the patent enables use of higher-strength materials that exceed NACE hardness requirements. The threading process does not have the same material hardness constraints as welding, allowing selection of materials optimized for collapse resistance without incurring the cost and complexity of NACE-approved welding procedures.
4Productivity
If the main bore internal diameter is maximized, then throughput is improved, but the lateral leg becomes more susceptible to formation pressures
Solution Approach 1:
The asymmetric design allows the main bore to be maximized in diameter for optimal throughput while the lateral leg maintains a round cross-section for pressure resistance. The D-shaped lateral bore opening is configured to receive a round lateral leg, creating a geometry where the main flow path is enlarged but the lateral connection remains structurally sound against formation pressures.
Data Source
AI summary
A multilateral junction comprising a y-block, lateral legs, and a transition sub for use in downhole well environments. The y-block includes a main bore and lateral bores with main bore and the lateral bores having threaded interfaces. The transition sub also includes lateral bores with threaded interfaces for receiving the lateral legs that also have threaded interfaces. The threaded interfaces of the lateral bore of the y-block has a less number of threads than the threaded interfaces of the lateral bores of the transition sub. The lateral leg includes another threaded interface that couples with the threaded interface of the lateral bore. Another end of each lateral leg includes an interface, e.g. a threaded interface, which couples with an interface of a transition sub. The main bore has an internal diameter that is greater than the internal diameter of the lateral bore.