Passive RFID Sensor Coil for Wellbore Sealant Monitoring
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Solution Overview
Problem
Current methods for monitoring wellbore sealant conditions in subterranean formations are inadequate due to limitations in active, embeddable sensors, such as sensitivity to alkali environments and electromagnetic noise, and the need for continuous power, which reduces their effectiveness and lifespan.
Innovation Solution
The use of MEMS-based data sensors and RFID tags embedded in wellbore sealants, which are passive and do not require continuous power, allowing for the monitoring of parameters like moisture content, temperature, and ion concentration over the sealant's service life, and can detect the location and condition of sealants within the wellbore.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If active electronic sensors are embedded in sealant, then real-time monitoring of sealant conditions is achieved, but sensor reliability deteriorates due to alkali damage and electromagnetic noise sensitivity
Solution Approach 1:
The patent replaces active electronic sensors with passive RFID tags that have no electronic circuitry requiring power. The RFID tags utilize electromagnetic backscatter communication, where the tag modulates the RF field by changing its impedance based on sensor measurements, eliminating susceptibility to alkali damage and electromagnetic noise while maintaining monitoring capability.
Solution Approach 2:
The patent employs disposable RFID tags embedded in sealant that require no power source and have no moving parts. These tags are designed to be inexpensive and replaceable, with the sensor element being a simple passive structure that can withstand harsh wellbore environments without degradation from electronic components.
2Duration of action of moving object
If active sensors with internal batteries are used, then continuous monitoring is enabled, but device size increases and service life decreases
Solution Approach 1:
The patent extracts the power source (battery) from the sensing system entirely. The RFID tags are completely passive, drawing no power from internal sources. Instead, they harvest energy temporarily from the incident RF field during interrogation, enabling indefinite service life without increasing device size with battery compartments and power management circuitry.
Solution Approach 2:
The RFID tags utilize the interrogating RF field itself to power their operation temporarily during each measurement cycle. The tag's sensor elements passively detect environmental conditions and modulate the RF field to transmit data, requiring no internal power source or active electronics, thus eliminating size constraints and enabling prolonged deployment.
3Reliability
If passive RFID tags are used instead of active sensors, then sensor reliability and service life are improved, but measurement precision may be affected
Solution Approach 1:
The patent employs sensor elements that detect environmental parameters (moisture, temperature, pH) and translate them into impedance changes. These impedance variations modulate the RF field's amplitude, phase, or frequency characteristics, allowing precise measurements to be encoded in the passive tag's electromagnetic response without requiring active electronics.
Solution Approach 2:
The patent uses the RF field itself as an intermediary carrier for measurement data. The passive sensor elements modulate the incident RF field by changing their electrical impedance in response to environmental conditions, and the interrogator system detects these modulations to retrieve precise measurement information without direct electrical contact or active components in the harsh environment.
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 prolonged sealant service life, reduced maintenance costs, and improved remediation methods by providing real-time data on sealant integrity and performance, enhancing the monitoring of sealant conditions during placement, curing, and throughout its service life.
Implementation Method 1
The sensor assembly includes an RFID sensor assembly including at least one third order bandpass filter including a single turn coil forming a center inductor for monitoring RFID tags
Data Source
AI summary
A communication assembly including at least one sensor assembly made up of interrogation circuitry and one or more antennae. The interrogation circuitry comprises at least one inductor coil sensor including a single turn coil inductor for reception of signals from the MEMS data sensors.