Smart Well Plug for Barrier Integrity Monitoring
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Solution Overview
Problem
Existing methods for inspecting the integrity of barriers in underground wellbores, such as cement plugs, are susceptible to inaccurate pressure measurements due to temperature fluctuations and leakage in long drill strings or coiled tubing, leading to unreliable fluid leak detection.
Innovation Solution
A smart test plug system with expandable seals, a pump, pressure gauges, and a mechanism for transmitting pressure data to the surface, which includes a pair of expandable seals to seal off the annular space, a pump for creating pressure differences, and pressure gauges to monitor and transmit pressures to a display for integrity assessment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pressure is monitored at the upper end of the drill string or coiled tubing, then the test method can be implemented with existing equipment, but the measurement accuracy deteriorates due to temperature fluctuations and leakage over long distances
Solution Approach 1:
The patent introduces an intermediary device (smart test plug with integrated pressure sensor) that transfers the measurement function from the surface monitoring point to the downhole location. The pressure sensor is embedded within the test plug itself, acting as an intermediary that directly measures wellbore pressure without transmitting signals through the long drill string, thereby eliminating temperature and leakage effects on measurement accuracy
Solution Approach 2:
The patent replaces the mechanical transmission system (pressure transmission through fluid in drill string) with an electronic sensing system (integrated pressure sensor and telemetry). Instead of relying on mechanical pressure transmission over long distances which is affected by temperature and leakage, the system uses electronic pressure measurement and wireless/electrical signal transmission through the wireline, which is immune to these environmental factors
2Reliability
If a simple plug design is used, then the device complexity is reduced, but the reliability of barrier integrity monitoring deteriorates due to susceptibility to temperature fluctuations and leakage
Solution Approach 1:
The patent merges multiple functions (sealing, pressure measurement, fluid injection, and data transmission) into a single integrated test plug device. The pressure sensor, pump, and telemetry system are combined within the plug body, eliminating the need for separate surface equipment and long drill strings, thereby improving reliability while managing complexity through functional integration
Solution Approach 2:
The patent implements a feedback system where the pressure sensor continuously monitors wellbore pressure and transmits data to the surface in real-time. This feedback mechanism allows for immediate detection of pressure changes indicating barrier leakage or temperature effects, enabling corrective actions and improving overall monitoring reliability through continuous verification
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 smart test plug system provides accurate and reliable integrity monitoring by minimizing the impact of temperature fluctuations and leakage, ensuring precise detection of fluid leaks and sealing performance, thereby ensuring the integrity of wellbore barriers.
Implementation Method 1
a pair of expandable seals configured to seal off an annular space between the plug and surrounding inner surface of the wellbore
Implementation Method 2
a pump for pumping fluid through a fluid channel traversing the plug between a lower wellbore section located between the plug and the barrier and an upper wellbore section located above the plug
Implementation Method 3
pressure gauges for monitoring pressure in the upper and lower wellbore sections and in the annular space
Data Source
AI summary
A test plug is proposed for inspecting the integrity of a cement plug or other barrier in an abandoned oil and/or gas production wellbore as well as its own sealing performance. The test plug employs a pair of expandable seals for sealing off an annular space between the seals, the plug and surrounding inner surface of the wellbore. Furthermore, it employs a pump for pumping fluid through a fluid channel traversing the plug into or from an intermediate wellbore section between the plug and the barrier. Valves are provided for closing the fluid channel after the pressure in the intermediate wellbore section has reached a selected level. Pressure gauges monitor a pressure in the intermediate wellbore section and in the annular space during a selected period of time. The monitored pressure is stored in a memory device and/or transmitted to a barrier and seal integrity monitoring display at the earth surface.