Capacitive Well Bore Fluid Sensor With Insulated Plates
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Solution Overview
Problem
Existing well bore fluid monitoring systems face challenges in withstanding elevated pressures and temperatures, are costly, and have limited useful life due to complex configurations, which complicates their deployment and maintenance in harsh downhole environments.
Innovation Solution
A well bore fluid sensor system comprising an inner plate, multiple outer plates, cable fixtures, and an electronics module with a resonant circuit and power supply, designed to be capacitively coupled and electrically insulated, allowing for effective fluid type detection based on capacitance and resistance measurements without direct contact with the fluid, thus preventing shorting and extending sensor life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional capacitance sensors with two plates in contact with well fluid are used, then fluid monitoring is enabled, but saltwater causes shorting and sensor failure
Solution Approach 1:
The patent introduces an intermediary insulating layer between the sensor plates and the well fluid. This insulating layer prevents direct contact between the conductive plates and saltwater, eliminating the shorting path while still allowing capacitance measurement through the insulator. The insulating layer acts as a mediator that enables the measurement function while blocking the harmful electrical conduction.
2Reliability
If robust sensors designed to withstand elevated pressures and temperatures are used, then downhole deployment is enabled, but manufacturing cost increases
Solution Approach 1:
The patent employs parameter changes by selecting materials with specific physical properties suitable for downhole conditions. The insulating layer and sensor structure are designed with material parameters (dielectric strength, thermal stability, pressure resistance) that enable operation at elevated temperatures and pressures while maintaining cost-effectiveness through optimized material selection rather than excessive robustness.
3Measurement precision
If complex impedance circuits are used to measure conductive and dielectric properties, then comprehensive fluid characterization is achieved, but device size and complexity increase
Solution Approach 1:
The patent segments the measurement function into distinct capacitive sensing elements with specific geometric configurations. By dividing the sensor into multiple insulated plates or plate pairs, each segment can independently measure different aspects of fluid properties. This segmentation allows comprehensive fluid characterization through multiple simple capacitance measurements rather than one complex impedance circuit.
4Measurement precision
If complex sensor configurations are used to enhance measurement capability, then measurement accuracy improves, but useful life decreases
Solution Approach 1:
The insulating layer serves as a protective intermediary that shields the internal sensor plates from direct exposure to corrosive well fluids. This mediator prevents chemical degradation and electrical shorting, thereby extending the sensor's operational life while maintaining measurement accuracy through the insulated capacitance measurement mechanism.
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 reliable and cost-effective fluid monitoring in harsh well bore conditions by maintaining sensor integrity and extending its useful life, while enabling accurate detection of fluid types and water presence without being affected by saltwater, thus overcoming the limitations of existing sensors.
Implementation Method 1
The inner plate is capacitively coupled to the first outer plate and the second outer plate
Implementation Method 2
the electronics module includes a resonant circuit and a power supply
Data Source
AI summary
A well bore fluid sensor is provided that includes an inner plate, a plurality of outer plates, first and second cable fixtures, and an electronics module. The inner plate defines a sensor interior cavity. The outer plates include a first outer plate and a second outer plate. The electronics module includes a resonant circuit and a power supply and is in signal communication with the inner plate and at least one of the first and second cable fixtures. The inner plate, the first and second outer plates, and the first and second cable fixtures are coupled together to form a unitary structure. The inner plate is electrically insulated from the first and second outer plates, the first and second cable fixtures. The first and second outer plates are electrically insulated from one another. The inner plate is capacitively coupled to the first and second outer plates.