Angled-Bore Y-Block Junction for High-Pressure Lateral Access
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Solution Overview
Problem
The challenge is to develop a pressure-tight multilateral junction that can be installed in casing and allow for selective access to a main wellbore, particularly for coiled tubing conveyed stimulation and clean-up operations, while ensuring high-pressure integrity and compatibility with existing wellbore structures.
Innovation Solution
A y-block design with angled bores and a housing that includes a single first bore and two branching bores, allowing for equal and selective access to both legs, featuring a blunt stress relief point to prevent collapse under pressure, and capable of withstanding high pressures up to 10,000 psi, enabling efficient access and fracturing of both main and lateral wellbores.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a multilateral junction is installed in casing to allow selective access to main wellbore, then access efficiency to lateral wellbores is improved, but maintaining high-pressure integrity (up to 10,000 psi) becomes more difficult
Solution Approach 1:
The junction is divided into multiple pressure-containing bores (first bore for main wellbore, second and third bores for lateral wellbores) that are segmented and isolated from each other. Each bore can independently maintain pressure integrity while allowing selective access to different wellbores, resolving the contradiction between access efficiency and pressure integrity.
Solution Approach 2:
The y-block junction is nested within the existing casing structure, with multiple bores nested within the housing. This nesting arrangement allows the junction to fit within the constrained casing space while maintaining multiple pressure-containing pathways for selective access to different wellbores.
2Adaptability or versatility
If a y-block design with angled bores is used to provide selective access, then operational flexibility is improved, but structural strength under high pressure deteriorates
Solution Approach 1:
The housing is designed with non-uniform wall thickness, with thicker walls at critical stress points and thinner walls where space is needed for angled bores. This local quality variation maintains structural strength in high-stress areas while allowing the angled bore configuration for operational flexibility in other areas.
Solution Approach 2:
The design incorporates a blunt stress relief point at the apex where the angled bores meet, which beforehand cushions and redistributes the high pressure loads before they can concentrate and cause structural failure, allowing the angled configuration to maintain both flexibility and strength.
3Productivity
If multiple lateral wellbores are accessed simultaneously, then stimulation treatment efficiency is improved, but pressure control and safety deteriorate
Solution Approach 1:
The junction provides segmented, isolated access pathways to different lateral wellbores through separate bores. This segmentation allows simultaneous stimulation treatments in multiple lateral wellbores while maintaining independent pressure control in each pathway, preventing pressure interference and safety hazards between adjacent operations.
Data Source
AI summary
Provided is a y-block, a multilateral junction, and a method for forming a well system. The y-block, in one aspect, includes a housing having a first end and a second opposing end, and a single first bore extending into the housing from the first end, the single first bore defining a first centerline. The y-block according to this aspect further includes second and third separate bores extending into the housing and branching off from the single first bore, the second bore defining a second centerline and the third bore defining a third centerline, wherein the second and third centerlines are angled relative to one another.