Downhole Alignment Sensor Assembly for Centered Casing Entry
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Solution Overview
Problem
Existing methods for gaining hydraulic access to an inaccessible cased wellbore, such as during a blowout or improper abandonment, lack effective alignment tools for precise drilling and milling operations.
Innovation Solution
A downhole alignment tool with a guidance device and sensor assembly that uses electromagnetic fields to determine the alignment of a casing milling device, utilizing sensors displaced at specific angles to measure distance and angular orientation relative to the casing, enabling precise alignment for drilling and milling operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional drilling methods are used to gain hydraulic access to cased wellbore, then the operation can be performed, but the alignment precision and success rate are insufficient
Solution Approach 1:
The patent replaces traditional mechanical alignment methods with electromagnetic field-based sensing. The sensor assembly uses electromagnetic coils to detect the position and orientation of the casing mill relative to the wellbore axis, providing precise alignment information without mechanical contact. This substitution enables accurate measurement of angular orientation and distance, directly improving alignment precision and operational success rate.
Solution Approach 2:
The patent introduces an intermediary sensing system that mediates between the casing mill and the wellbore structure. The sensor assembly with multiple electromagnetic coils acts as an intermediary to detect and measure the spatial relationship between the milling tool and the wellbore, providing real-time alignment data that guides precise positioning without direct mechanical interference.
2Measurement precision
If sensor assembly with multiple coils is used, then alignment measurement capability is improved, but device complexity increases
Solution Approach 1:
The patent segments the sensing function into multiple independent electromagnetic coils arranged in specific patterns. Each coil or coil pair detects a specific component of the electromagnetic field, allowing the system to measure both distance and angular orientation separately. This segmentation enables complex measurement capabilities while keeping each individual sensor element relatively simple.
Solution Approach 2:
The sensor assembly with multiple electromagnetic coils serves multiple functions simultaneously: it measures distance to the casing mill, determines angular orientation, and provides alignment information. This multi-functionality is achieved through a single integrated sensor assembly that processes various electromagnetic field interactions, reducing the need for separate measurement devices and thereby managing overall system complexity.
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
Enhances the success rate and efficiency of casing entry operations by ensuring the milling process is centered on the casing, improving access and reducing the risk of misalignment during wellbore interventions.
Implementation Method 1
Oscillator electronics energize the exciting coils such that a first electromagnetic field from the first and fourth exciting coils is out of phase with a second electromagnetic field from the second and third exciting coils
Implementation Method 2
An evaluation unit uses the sensing coil to detect a signal phase and amplitude resulting from the electromagnetic fields to determine distance from an object based on the signal amplitude and angular orientation relative to the object based on the signal phase
Data Source
AI summary
A downhole alignment tool includes a guidance device, the guidance device having a center and a reference mark and a downhole sensor assembly, the downhole sensor assembly attached or positioned within the guidance device. The guidance device includes electronics, the electronics including an oscillator, an evaluation unit, and an output stage. A sensor detects a signal supplied to the evaluation unit for determining orientation of the reference mark relative to an object, such as another wellbore or casing.