Downhole Leak Detection Using Virtual Sensor Arrays
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Solution Overview
Problem
Current downhole leak detection methods using multiple sensors are costly and impractical, often resulting in inaccurate leak location identification due to sensor malfunctions and environmental challenges, especially when deploying sensors along production tubing.
Innovation Solution
A system utilizing a single physical sensor deployed on a retractable string, such as a wireline or drill string, that travels along the wellbore to detect leaks by recording physical signals at high sampling rates, forming a virtual sensor array through correlated sequences, and applying beamforming algorithms to determine leak locations accurately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple sensors are deployed along production tubing to detect leaks, then leak detection accuracy is improved, but cost and device complexity increase proportionally with the number of sensors
Solution Approach 1:
The patent creates virtual copies of physical sensors through signal processing. A single physical sensor generates multiple virtual sensor signals by applying different beamforming weights and spatial filtering techniques, effectively multiplying the sensing capability without adding physical sensors. This resolves the contradiction by achieving multi-sensor detection accuracy with single-sensor hardware.
Solution Approach 2:
The patent changes the operational parameters of a single sensor by dynamically adjusting beamforming weights, spatial filtering parameters, and signal processing configurations. These parameter changes enable the single sensor to function equivalently to multiple sensors with fixed spatial positions, resolving the contradiction between measurement precision and device complexity.
2Measurement precision
If multiple sensors are deployed to obtain accurate leak location information, then spatial resolution is improved, but reliability decreases due to sensor malfunctions and environmental challenges
Solution Approach 1:
By creating virtual sensor copies through signal processing rather than deploying multiple physical sensors, the system eliminates reliability issues associated with physical sensor malfunctions. The virtual sensors are mathematical constructs that cannot fail mechanically, yet provide the same spatial resolution benefits, resolving the contradiction between measurement precision and reliability.
Solution Approach 2:
The single physical sensor serves multiple functions simultaneously - it acts as all the virtual sensors needed for spatial resolution while being maintained by a single physical unit. This self-service approach eliminates the reliability problems of multiple independent sensors while maintaining spatial resolution through sophisticated signal processing.
3Measurement precision
If an array of multiple sensors is deployed to detect leaks, then leak detection capability is improved, but ease of operation deteriorates due to difficulty in deploying and operating multiple sensors
Solution Approach 1:
The patent replaces the operational complexity of deploying and managing multiple physical sensors with the computational task of generating virtual sensor signals from a single physical sensor. This transformation converts a physically complex operation into a computationally manageable task, resolving the contradiction between leak detection capability and ease of operation.
Solution Approach 2:
The patent extracts the essential sensing function from multiple physical sensors and consolidates it into a single physical sensor with enhanced signal processing. By taking out the redundant physical hardware and retaining only the necessary sensing capability through virtualization, the system improves ease of operation while maintaining detection capability.
Data Source
AI summary
The disclosed embodiments include a method of downhole leak detection. The method of downhole leak detection includes obtaining physical signals detected by at least one physical sensor traveling along a wellbore. Additionally, the method includes detecting correlated sequences from the physical signals and constructing a covariance matrix based on the correlated sequences. The method also includes computing a spatial spectrum indicative of a location of a leak based on the covariance matrix.