Variable Diameter Wellbore Compensator for Axial Load Management
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Solution Overview
Problem
Wellbore completion strings, particularly in openhole multistage completions, face significant axial loads during hydraulic fracturing, leading to deformation and potential loss of zonal isolation due to temperature and pressure changes, which existing technologies fail to adequately address.
Innovation Solution
A wellbore assembly featuring a compensator tube with sections of reduced or increased diameter made from expandable tubular metallurgy, which adjusts its length under axial loads to maintain integrity and prevent deformation, coupled with packers to secure the tube within the wellbore, allowing it to accommodate changes in length without compromising the tubing's integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rigid wellbore string is used to maintain structural integrity, then strength and reliability are improved, but the string cannot accommodate axial load changes and temperature/pressure variations, leading to deformation and loss of zonal isolation
Solution Approach 1:
The wellbore string incorporates a dynamic section with variable cross-sectional area that can change its length in response to axial loads. This dynamic portion allows the string to adapt its configuration under varying thermal and mechanical conditions, preventing deformation and maintaining zonal isolation while accommodating expansion or contraction of the wellbore string.
Solution Approach 2:
The patent changes the physical parameter of the tubular structure by introducing a portion with variable cross-sectional area that can alter its length. This parameter change enables the wellbore string to respond to axial loads and temperature/pressure variations, resolving the contradiction between maintaining structural integrity and accommodating dimensional changes.
2Adaptability or versatility
If the wellbore string is made flexible to accommodate length changes, then adaptability is improved, but structural integrity and strength may be compromised
Solution Approach 1:
The wellbore string features a localized portion with variable cross-sectional area rather than making the entire string flexible. This local quality change allows the specific section to accommodate length changes while the rest of the string maintains its structural integrity and strength, resolving the contradiction between flexibility and strength.
Solution Approach 2:
The wellbore string is segmented into different functional portions: rigid sections that maintain structural integrity and a dynamic section with variable cross-sectional area that accommodates length changes. This segmentation allows each portion to perform its specific function, balancing strength and adaptability.
3Reliability
If conventional wellbore strings are used, then device complexity is reduced, but they cannot compensate for thermal expansion and contraction during hydraulic fracturing operations
Solution Approach 1:
The patent implements a portion with variable cross-sectional area that can change its length in response to thermal and mechanical loads. This parameter change capability enables the wellbore string to compensate for thermal expansion and contraction during hydraulic fracturing operations, improving reliability while adding controlled complexity to the structure.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The compensator tube effectively mitigates casing deformation and maintains pipe integrity by adjusting its length in response to axial loads, ensuring zonal isolation and simplifying the completion process, thereby facilitating future wellbore interventions.
Implementation Method 1
The portion of reduced or increased diameter defining an internal diameter that changes, with the first tube under a compression load, to decrease a length of the first tube. The internal diameter changes, with the first tube under a tensile load, to increase a length of the first tube
Implementation Method 2
The portion of reduced or increased diameter bends or flexes under axial stress to reduce or increase the length of the first tube
Data Source
AI summary
A wellbore assembly includes a first tube and a second tube. The first tube is disposed within a wellbore and has a first end fixed with respect to a wall of the wellbore. The second tube is coupled to a second end of the first tube. The second tube has a third end opposite the coupling and fixed with respect to the wall of the wellbore. The first tube includes a portion of reduced or increased diameter residing between the first end and the second end. The portion of reduced or increased diameter defines an internal diameter that changes, with the first tube under a compression load, to decrease a length of the first tube. The internal diameter changes, with the first tube under a tensile load, to increase a length of the first tube to accommodate changes in length of the first tube or the second tube or both.