Non-magnetic Sensor Assembly for Downhole Flow Rate Detection
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Solution Overview
Problem
Current downhole operations face challenges in accurately measuring fluid properties such as flow rate and density, which affect tool performance and efficiency, due to limitations in existing sensing technologies.
Innovation Solution
A sensor assembly is introduced, comprising a housing with a non-magnetic material, a shaft, bearings, and an impeller with a magnetized portion, which rotates within the fluid flow, allowing for the detection of rotational velocity and axial distance to determine fluid properties using an electronics assembly and actuation mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional magnetic sensors are used to detect impeller rotation, then the sensing mechanism is simple, but the housing material is constrained to be magnetic which interferes with sensor operation
Solution Approach 1:
The patent introduces a non-magnetic housing as an intermediary structure that allows magnetic field penetration from the impeller magnet to the sensor. This resolves the conflict by providing a housing material that is both manufacturable and compatible with magnetic sensing, as the non-magnetic material does not interfere with the magnetic field while still providing structural support.
2Measurement precision
If the impeller rotates at high speed to improve flow measurement sensitivity, then measurement precision improves, but the mechanical stability and bearing load increase
Solution Approach 1:
The patent employs dynamic balancing of the impeller and optimized bearing support structures to enable high-speed rotation while maintaining mechanical stability. The bearing assembly is designed to accommodate high rotational speeds with appropriate load capacities, and the impeller geometry is optimized to minimize unbalanced forces that would compromise mechanical stability at high speeds.
3Measurement precision
If the sensor assembly is positioned close to the impeller for accurate detection, then measurement precision improves, but the axial distance variability increases
Solution Approach 1:
The patent incorporates feedback mechanisms through the sensor assembly that can detect and compensate for axial position variations. The sensor system monitors the magnetic field strength and uses this information to adjust measurements, compensating for changes in axial distance between the impeller magnet and sensor, thereby maintaining measurement precision despite positioning tolerances.
4Ease of operation
If a hydraulic brake is added to control impeller speed, then flow rate control improves, but the device complexity increases
Solution Approach 1:
The patent utilizes hydraulic principles by allowing the drilling fluid flow itself to drive the impeller, eliminating the need for complex mechanical drive mechanisms. The fluid's kinetic energy directly rotates the impeller, and flow rate control is achieved by controlling the fluid supply, leveraging hydraulic principles to simplify the overall system while maintaining ease of operation.
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
This solution enables precise measurement of fluid properties, enabling effective actuation of downhole tools and optimizing their performance by accurately determining flow rates and densities, thereby enhancing operational efficiency.
Implementation Method 1
The sensor may be proximate the magnetized portion or within the interior chamber, and may detect the magnetized portion of the impeller
Implementation Method 2
An impeller may be positioned around the shaft and the bearing, and may include a magnetized portion. As fluid is pumped into the wellbore, the fluid may cause the impeller to rotate
Data Source
AI summary
A sensor assembly may include a housing made of a non-magnetic material. The housing may define an interior chamber. A shaft may extend from the housing. A bearing may be positioned around the shaft. An impeller may be positioned around the shaft and the bearing, and the impeller may include a magnetized portion. A sensor may be positioned within the interior chamber and/or proximate the magnetized portion. The sensor may detect the magnetized portion of the impeller to sense a rate of rotation of the impeller. The rate of rotation of the impeller may correspond to changes in flow rate of the fluid. As the flow rate of the fluid, and the rate of rotation of the impeller change in predetermined manners, control signals may be conveyed to activate a tool.