Downhole Sensor Assembly Using EM Fields for Casing Mill Alignment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for gaining hydraulic access to an existing cased wellbore are inefficient and prone to errors during operations like blowout control, well abandonment, and tubular removal, necessitating improved alignment tools for precise drilling and milling.
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 separated by specific angles to measure distance and angular orientation relative to the casing, ensuring accurate positioning for drilling and milling operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional methods are used to gain hydraulic access to existing cased wellbores, then the operations can be performed, but the alignment precision and success rate are insufficient
Solution Approach 1:
The patent replaces traditional mechanical alignment methods with an electromagnetic field-based sensing system. The sensor assembly uses electromagnetic fields to detect the position and orientation of the casing mill relative to the wellbore center, providing precise alignment measurements without mechanical contact or visual reference markers.
Solution Approach 2:
The patent introduces an electromagnetic field as an intermediary between the casing mill and the sensing system. The electromagnetic fields interact with the conductive casing to create detectable signals that encode positional and orientational information, enabling indirect but precise measurement of alignment status.
2Loss of information
If sensors are positioned to measure both distance and angular orientation, then comprehensive alignment information is obtained, but the device complexity increases
Solution Approach 1:
The patent combines multiple sensing functions into a single integrated sensor assembly. The sensor assembly simultaneously measures distance, angular orientation, and alignment status by using multiple electromagnetic sensors positioned at specific angles relative to each other, eliminating the need for separate measurement systems.
Solution Approach 2:
The sensor assembly is designed as a multi-functional system that performs multiple measurement tasks simultaneously. The same electromagnetic sensing mechanism provides both distance measurement, angular orientation data, and alignment verification, making the system universally applicable to various wellbore intervention operations.
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 allowing precise alignment of the milling process at the centerline of the casing, improving access and reducing operational risks.
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.