Magnetic Ranging Through Cased Wells Using Sensor Positioning
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Solution Overview
Problem
Magnetic ranging between downhole tools is hindered when both wells are cased, as the magnetic fields are shielded by the casing, making it difficult to determine the location and proximity of one well relative to another during sidetracking to avoid collisions.
Innovation Solution
A method involving positioning a magnetic source in the target well and a magnetic sensor in the drilling well, measuring the magnetic field while moving the sensor through the drilling well to identify unsaturated locations, and determining the direction and range to the target well by accounting for interference and shielding effects caused by the casing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetic ranging is performed between two cased wells, then the wellbore location and proximity information can be obtained, but the magnetic fields are shielded by the casing making measurement difficult
Solution Approach 1:
The patent applies preliminary action by moving the magnetic sensor through the drilling well before performing the actual ranging measurement to identify locations where the sensor is not saturated. This preliminary scanning allows the system to select optimal measurement positions that avoid casing shielding effects, thereby enabling accurate magnetic field measurements between cased wells.
Solution Approach 2:
The patent changes the spatial parameter by moving the magnetic sensor to different positions within the drilling well. By varying the sensor's location, the system identifies positions where magnetic saturation does not occur, allowing the magnetic field measurement to penetrate the casing shielding and obtain accurate ranging data between the two cased wells.
2Measurement precision
If the magnetic sensor is moved through the drilling well to find unsaturated locations, then accurate measurement can be achieved, but the measurement process becomes more complex
Solution Approach 1:
The system applies self-service by automatically moving the magnetic sensor through the drilling well and autonomously identifying locations where the sensor is not saturated. The system self-adjusts to find optimal measurement positions without requiring external intervention, thereby achieving precise measurements while managing the complexity through automated processes.
Solution Approach 2:
The patent implements feedback by continuously monitoring the magnetic field strength at different sensor positions and using this information to identify locations where the sensor is not saturated. This feedback mechanism allows the system to adaptively select measurement positions, ensuring accurate data collection while systematically managing the measurement process complexity.
3Measurement precision
If magnetic ranging is performed between uncased drilling well and cased target well, then magnetic field measurement is possible, but the drilling well must remain uncased which limits operational flexibility
Solution Approach 1:
The patent applies preliminary action by first moving the magnetic sensor through the drilling well to identify unsaturated locations before performing the ranging measurement. This allows the drilling well to be cased while still achieving accurate magnetic field measurements, as the preliminary scanning identifies positions where the casing does not cause sensor saturation.
Solution Approach 2:
The patent changes the spatial parameter of the sensor position to overcome the limiting effect of the cased drilling well. By adjusting the sensor's location within the well, the system finds positions where magnetic saturation is avoided, thereby enabling magnetic ranging between two cased wells and restoring operational flexibility.
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
Enables accurate determination of the direction and range to the target well, even when both wells are cased, thereby preventing collisions during sidetracking by identifying suitable measurement locations and compensating for casing interference.
Implementation Method 1
a magnetic source in the target well. The magnetic field from the magnetic source may extend to the drilling well
Implementation Method 2
a magnetic sensor in the drilling well... measuring the magnetic field in the drilling well as the magnetic sensor is moved through the drilling well
Implementation Method 3
where the drilling well is cased, magnetic fields from the target well may be shielded or perturbed by the casing
Data Source
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AI summary
A method for determining the direction and/or range from a drilling well to a target well may include positioning a magnetic source in the target well and a magnetic sensor in the drilling well. The method may include activating the magnetic source in the target well and moving one or both of the magnetic source and magnetic sensors until a location in which the magnetic sensor is not saturated is identified. The method may include determining the direction and/or range to the target well at that location.