Adjustable Sensor Mounts for Downhole Acoustic Imaging
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Solution Overview
Problem
Conventional acoustic tools face challenges in accurately imaging through wellbore casing due to difficulties in separating casing reverberation signals from signals of interest, especially when the interface behind the casing is not normal to the incident waveform, making it hard to define the cement/formation boundary and interface.
Innovation Solution
The use of adjustable sensor mounts with variable radial placement of acoustic sensors, including pitch-catch transducers, allows for precise positioning of sensors relative to the casing, enhancing imaging capabilities and minimizing unwanted noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional acoustic tools are used with fixed sensor positioning, then the tool structure is simple, but the sensor sensitivity to distance variations causes poor measurement precision when imaging through casing
Solution Approach 1:
The patent implements adjustable sensor mounts that enable dynamic radial positioning of acoustic sensors relative to the casing. This allows the sensor distance to be optimized for different casing diameters and imaging requirements, resolving the contradiction between measurement precision and fixed structure by making the positioning system adaptable rather than static
Solution Approach 2:
The patent changes the radial distance parameter of sensor placement from a fixed value to a variable that can be adjusted based on casing dimensions and imaging needs. This parameter change enables optimal sensor positioning for different measurement scenarios, improving imaging precision without requiring a completely new tool design
2Reliability
If sensors are positioned closer to the casing to improve signal strength, then signal-to-noise ratio improves, but casing reverberation signals become more dominant and harder to separate
Solution Approach 1:
The adjustable sensor mount allows dynamic optimization of sensor-to-casing distance. By enabling fine-tuned positioning, the system can find the optimal distance that balances signal strength acquisition against reverberation interference, resolving the contradiction between signal quality and harmful reverberation effects
Solution Approach 2:
The system uses acoustic waveform information and signal analysis to provide feedback on the quality of received signals. This feedback mechanism enables real-time or post-processing optimization of sensor positioning to minimize reverberation interference while maintaining strong signal acquisition
3Adaptability or versatility
If the tool is designed to adapt to different casing sizes, then versatility is improved, but the complexity of the positioning mechanism increases
Solution Approach 1:
The adjustable sensor mount serves multiple functions: it positions sensors for different casing diameters, optimizes radial distance for imaging, and enables adaptation to various well conditions. This multi-functionality resolves the contradiction by making a single component responsible for multiple requirements rather than needing separate systems for each function
Solution Approach 2:
The patent employs adjustable and potentially collapsible framework elements that can dynamically adapt to different casing sizes. This dynamic capability provides versatility across various applications without requiring completely different tool configurations for each casing type
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 approach improves the acquisition of acoustic waveform information, providing clearer images of the cement and formation interfaces, thus enhancing the integrity evaluation of the casing and reducing signal interference.
Implementation Method 1
transmitters to create pressure waves inside the borehole fluid, which in turn create several types of waveguide modes in the borehole. Corresponding modes of propagation occur in the formation surrounding the borehole
Data Source
AI summary
A downhole sensor position adjustment device on a downhole sensor assembly comprising a set of centralizers and a sensor array coupled to an adjustable framework radially positionable by an actuator. The actuator includes an extend-retract mechanism to radially position the sensor array a predetermined radial distance to an inner surface of a casing. A controller communicatively coupled to the extend-retract mechanism is configured to actuate the extend-retract mechanism. A positioning sensor provides feedback of the predetermined radial distance of the sensor array to the inner surface of the casing.