Segmented Wireless Logging Tool Sensor Deployment
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Solution Overview
Problem
Downhole sensors for measuring fluid properties and flow in wellbores are often spaced far apart, leading to inaccurate readings due to varying fluid properties, and permanently disposed sensors obstruct fluid flow, increasing pressure drop and affecting measurement accuracy.
Innovation Solution
A logging tool with a mother tool and sensor assemblies that can be decoupled and anchored at different depths in the wellbore, allowing for accurate measurement of fluid pressure, temperature, flow, porosity, and resistivity without obstructing fluid flow, using a transceiver system for data communication between the sensors and the mother tool.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensors are spaced far apart in the wellbore, then installation is easier and obstruction of fluid flow is reduced, but measurement accuracy deteriorates due to varying fluid properties at different locations
Solution Approach 1:
The logging tool is divided into multiple sensor assemblies that can be independently deployed at different depths along the wellbore. Each assembly contains sensors for measuring fluid properties and flow, allowing localized measurements that capture spatial variations in fluid characteristics without requiring a single complex sensor system.
Solution Approach 2:
The sensor assemblies are designed to be movable and repositionable along the wellbore using the logging tool. The assemblies can be moved to different locations and secured at desired depths, enabling dynamic adjustment of measurement positions to optimize accuracy while minimizing fluid flow obstruction.
2Reliability
If permanently disposed sensors are used, then measurement continuity is improved, but fluid flow obstruction increases leading to higher pressure drop
Solution Approach 1:
The sensor assemblies are designed to be temporarily deployed and then retrieved, rather than permanently installed. This dynamic approach allows continuous measurement capability during the logging operation while avoiding permanent obstruction of fluid flow. The assemblies can be moved to different positions and removed when no longer needed, maintaining measurement continuity without sustained pressure drop.
Solution Approach 2:
The sensor assemblies are extracted from the wellbore after the logging operation is complete. By removing the sensors rather than leaving them permanently installed, the system eliminates ongoing obstruction of fluid flow while preserving the ability to perform repeated measurements through subsequent logging operations.
3Adaptability or versatility
If downhole tools are used to mount temporary sensors, then sensor deployment flexibility is improved, but measurement accuracy deteriorates due to tool interference with sensor readings
Solution Approach 1:
The sensor assemblies are extracted from the downhole tool after deployment. The logging tool carries multiple sensor assemblies that can be independently deployed at different depths, then the assemblies are removed from the tool body and secured in the wellbore at their measurement locations. This separation eliminates interference between the tool and sensors while maintaining deployment flexibility.
Solution Approach 2:
The sensor assemblies are segmented from the main logging tool body, allowing independent deployment and positioning. Each assembly can be detached and positioned at specific depths where measurements are needed, then secured independently. This segmentation provides deployment flexibility while eliminating tool interference with sensor readings.
Data Source
Figure 1~2A
Figure 2B~3
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AI summary
A system and method for logging in a wellbore where sensor assemblies on a logging tool are deployed and landed in the wellbore. After the sensor assemblies are landed in the wellbore and released from the logging tool, the logging tool is pulled uphole. Moving the logging tool uphole from where the sensor assemblies are landed, reduces interference of the logging tool with measurements obtained with the sensor assemblies. The sensor assemblies include sensors for detecting fluid flow, pressure, temperature, fluid density, formation resistivity, and which can be mechanical, optical, acoustic, or electromagnetic.