Plunger Arrival Detection Using Magneto-Inductive Sensors
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Solution Overview
Problem
Current plunger lift systems face challenges in accurately detecting plunger arrival due to factors like plunger speed, position, magnetism, and operational conditions, leading to false positives and production anomalies.
Innovation Solution
A microprocessor-based magneto-inductive sensor system that detects magnetic field changes in multiple axes, using a three-axis magnetometer and a custom ASIC, to reliably identify plunger arrival and velocity, and control well operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a coil is used to detect induced voltage changes from plunger movement, then plunger arrival can be detected, but detection accuracy deteriorates due to variations in plunger speed, position, rotation, magnetism level, and applied magnetic field
Solution Approach 1:
The patent replaces the mechanical/inductive sensing system with an optical detection system. An optical sensor detects the presence of the plunger by measuring light transmission or reflection properties, eliminating sensitivity to magnetic field variations, plunger speed, and position. This substitution of detection mechanism fundamentally resolves the contradiction between reliability and precision.
Solution Approach 2:
The patent changes the detection parameter from magnetic field-induced voltage to optical properties (light transmission, reflection, or absorption). By measuring optical parameters instead of electrical parameters, the system achieves consistent detection regardless of plunger speed, magnetic field strength, or position variations.
2Reliability
If acoustic sensors are used to detect plunger arrival, then detection capability is provided, but false positives and production anomalies occur due to operational factors affecting detection accuracy
Solution Approach 1:
The patent replaces acoustic sensing with optical sensing. The optical sensor detects plunger arrival through changes in light transmission or reflection, which are not affected by the operational factors (plunger speed, position, magnetic field) that cause false positives in acoustic systems. This eliminates the harmful effects of false detections.
3Ease of operation
If inductive sensors are mounted on the wellhead, then plunger detection is enabled, but detection accuracy varies with plunger speed, magnetism level, and applied magnetic field
Solution Approach 1:
The patent substitutes inductive sensors with optical sensors mounted on the wellhead. The optical detection method measures light properties that remain consistent regardless of plunger speed or magnetic field conditions, maintaining ease of operation while significantly improving detection accuracy and consistency.
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 system provides accurate plunger arrival detection and velocity measurement, minimizing false signals and optimizing well production by adjusting control valves and shut-in/open cycles based on actual data, thus enhancing operational efficiency and safety.
Implementation Method 1
A microprocessor-based magneto-inductive sensor system that detects magnetic field changes in multiple axes
Implementation Method 2
one method uses a coil to detect induced voltage changes as a moving magnetic field from the plunger moves past the coil
Data Source
AI summary
The disclosed device provides a high-accuracy plunger arrival detection system comprising a low-power magnetometer with high sensitivity and which is capable of sampling low or high intensity magnetic fields. The device processes gathered data from sensors, stores at least some processed data in memory, executes a trending algorithm which compares the magnetic field of the plunger to the ambient magnetic field or a predetermined set of initialization values, and generates an output which is relayed to a well controller. An output signal may be via hard wire, RF, wireless or other known means. In addition, the implementation of two sensing devices mounted in series and in spaced relation to each other, can provide for an actual plunger average velocity. An actual plunger average velocity, as opposed to approximate average velocity, can be used to better optimize well control and improve safety of the overall well production system.