Wireless Sensor Unit for Well Casing Annuli Pressure Monitoring
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Solution Overview
Problem
Current methods for monitoring pressure and temperature in well casing annuli of oil and gas production wells are inadequate, as they either compromise the well's pressure integrity or are impractical for permanent installation, especially when accessing outer annular spaces like Annulus-B and Annulus-C, which are crucial for modern well designs that utilize these spaces actively.
Innovation Solution
A non-intrusive wireless sensor system comprising a Wireless Sensor Unit (WSU) and Sensor Energizer Unit (SEU) that uses electromagnetic induction for power harvesting and communication, allowing for permanent monitoring of pressure and temperature without compromising the well's integrity, with sensors placed outside the non-magnetic casing to measure annular space conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensors are placed inside outer annuli (Annulus-B, C) to monitor pressure, then measurement capability is improved, but pressure containing integrity is compromised due to need to puncture wellhead housing or casing hanger
Solution Approach 1:
Instead of placing sensors inside the annular spaces (traditional approach), the patent inverts the approach by placing sensors on the exterior surface of the casing. The sensors measure pressure from the outside of the casing wall, eliminating the need to puncture or compromise the pressure containment barriers while still achieving pressure monitoring of the annular spaces.
Solution Approach 2:
The patent uses the casing wall itself as an intermediary medium. The sensors on the exterior surface measure pressure through the casing wall, using the wall as a mediator to transmit pressure information from the annular space to the sensors without requiring direct penetration of the containment barriers.
2Measurement precision
If hydraulic access is created to monitor pressure in outer annuli, then measurement capability is improved, but safety and integrity are worsened due to compromise of pressure containment barriers
Solution Approach 1:
The patent inverts the traditional approach of creating internal hydraulic access by placing sensors on the exterior of the casing. This eliminates the need to create any access points through the pressure containment barriers, thereby eliminating the safety risks associated with compromising these barriers.
3Reliability
If non-intrusive sensors are placed outside casing, then pressure integrity is maintained, but power and communication implementation becomes unsolved
Solution Approach 1:
The patent replaces mechanical/electrical power and communication systems with an electromagnetic field-based system. An electromagnetic transmitter inside the wellbore generates an electromagnetic field that penetrates the casing wall to power the exterior sensors and enable two-way communication, eliminating the need for physical connections through the casing.
Solution Approach 2:
The electromagnetic field acts as an intermediary medium to transfer both power and communication signals across the casing wall. The field penetrates the non-conductive casing material to establish electrical connection and data communication between the interior transmitter and exterior sensors without physical penetration.
4Productivity
If outer annuli are used as active process elements, then production capability is improved, but the need for barrier function is reduced, moving active barrier further out
Solution Approach 1:
The patent uses electromagnetic field technology to enable monitoring of multiple annular spaces without adding mechanical complexity to the wellhead or casing structure. The electromagnetic power and communication system provides a clean, non-intrusive solution that accommodates the complex multi-annulus production design without requiring corresponding mechanical complexity in the monitoring system.
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 real-time, accurate monitoring of pressure and temperature changes, distinguishing between process and environmental fluctuations and potential leaks, enhancing well safety and risk management by predicting future pressure profiles and allowing for timely interventions.
Implementation Method 1
converting the DC power supplied to the SEU on a cable from the surface to an alternating electromagnetic field that provides a source of power for the WSU outside the casing
Implementation Method 2
the WSU is powered by Power Harvesting wherein the frequency of the induction signal is in the range of 10-1000 Hz for deep penetration through the non-magnetic casing
Implementation Method 3
wherein the SEU and the WSU use an electromagnetic modulation technique to provide communication of data between the two components
Data Source
AI summary
An apparatus and method to provide monitoring of pressure outside the wellbore casing of a well in which a Wireless Sensor Unit is placed externally of a section of non-magnetic casing. An internal Sensor Energizer Unit is placed inside the wellbore casing. The Wireless Sensor Unit includes one or more sensors to measure the pressure and/or temperature of the surroundings. The Wireless Sensor Unit and the Sensor Energizer Unit communicate using electromagnetic modulation techniques, and the Wireless Sensor Unit may be powered by means of power harvesting from the Sensor Energizer Unit.