Downhole Tractor Positioning Mechanism for Decoupled Logging Speed
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Solution Overview
Problem
Existing wellbore logging operations face challenges in decoupling the speed of logging tools from the speed of downhole tractors, limiting optimal measurement accuracy and efficiency, especially in extended lateral wellbores where power limitations restrict tractor speed.
Innovation Solution
The implementation of a linear actuator positioned between the wireline tractor and the logging tool allows for independent control of the logging tool's speed relative to the tractor, enabling temporary adjustments to achieve optimal speeds for different logging operations, such as increasing relative speed for spinner tools or slowing for pulsed neutron logging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the downhole tractor speed is increased to improve logging efficiency, then productivity increases, but measurement precision deteriorates due to stick/slip phenomena and inability to maintain optimal logging speeds
Solution Approach 1:
The system segments the logging tool assembly into modular components (spinner tool, positioning mechanism, tractor) that can operate independently. The positioning mechanism can adjust the logging tool's speed relative to the tractor, allowing the tractor to maintain high speed for productivity while the logging tool operates at optimal speed for measurement precision.
Solution Approach 2:
The positioning mechanism acts as an intermediary between the downhole tractor and the logging tool. It decouples the speed relationship between the two components, enabling the tractor to travel at high speed while the logging tool maintains optimal logging speed, thus resolving the contradiction between productivity and measurement precision.
2Measurement precision
If the tractor speed is reduced to maintain optimal logging speeds, then measurement precision improves, but productivity deteriorates due to increased operation time
Solution Approach 1:
The logging system is segmented into independent speed-controlled components. The logging tool can be positioned and moved at optimal speeds for measurement precision while the tractor continues at higher speeds, eliminating the need to reduce overall system speed and maintaining productivity.
Solution Approach 2:
The positioning mechanism provides dynamic speed adjustment capability, allowing the logging tool speed to be independently controlled relative to the tractor. This dynamic adjustment enables optimal logging speeds to be maintained without constraining the tractor speed, thus preserving productivity while improving measurement precision.
3Measurement precision
If multiple passes are performed to achieve optimal measurement speeds, then measurement precision improves, but loss of time increases due to repeated operations
Solution Approach 1:
The positioning mechanism enables continuous optimal logging action during a single pass. By maintaining the logging tool at optimal speed throughout the traversal, the system eliminates the need for multiple passes, thus reducing time loss while preserving measurement precision.
Solution Approach 2:
The positioning mechanism is pre-configured to maintain optimal logging speeds before the logging operation begins. This preliminary setup ensures that the logging tool operates at optimal speed from the start of the pass, eliminating the need for speed adjustments or repeated passes and reducing overall operation time.
4Productivity
If the tractor speed is increased in extended lateral wellbores, then productivity improves, but measurement precision deteriorates due to power limitations restricting optimal logging speeds
Solution Approach 1:
The system segments the speed control function between the tractor (for efficient traversal) and the positioning mechanism (for optimal logging speed). This segmentation allows the tractor to overcome power limitations by traveling at higher speeds while the positioning mechanism ensures the logging tool maintains optimal speed for measurement precision in lateral wellbores.
Solution Approach 2:
The positioning mechanism serves as an intermediary that decouples the speed relationship between the tractor and logging tool. In extended lateral wellbores, this allows the tractor to operate at speeds optimized for power constraints while the logging tool operates at speeds optimized for measurement precision, resolving the contradiction between productivity and measurement accuracy.
Data Source
AI summary
Wellbore logging apparatus include a positioning mechanism that couples one or more well logging devices included in a well logging tool to a downhole tractor. The positioning tool allows the logging tools to be moved at a different rate of travel through a wellbore compared to the rate of travel of the downhole tractor through the wellbore.