Downhole Power Generation via Rectifier Diversion
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Solution Overview
Problem
Conventional methods for providing power to downhole tools in harsh wellbore environments face reliability issues due to long distances and harsh conditions, leading to degradation of electrical cabling and connectors, which limits the availability and reliability of power for tools like electronics, sensors, and actuators.
Innovation Solution
A system that uses a variable speed drive connected to a downhole electric motor via three-phase conductors, with a rectifier diverting power to downhole tools, providing direct current and smoothing the voltage to ensure reliable operation without dedicated power cables, utilizing magnetic bearings and local power generation to overcome distance and environmental challenges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If power is transmitted over long distances from surface to downhole tool using electrical cabling, then power can be supplied to downhole tools, but the cabling and connectors degrade due to harsh conditions and long distances, reducing reliability
Solution Approach 1:
The patent extracts the power transmission function from long-distance electrical cabling by implementing local power generation at the downhole tool using a generator coupled to the motor shaft, eliminating the need for power to travel through degraded cables over long distances
Solution Approach 2:
The patent introduces a rectifier as an intermediary device that converts AC power from the three-phase conductors to DC power for the downhole tool, and a local generator as an intermediary power source that provides additional power locally, reducing dependence on long-distance cable transmission
2Power
If dedicated power cables are used to supply power to downhole tools, then power transmission is possible, but the system complexity and cost increase due to additional cables and connectors
Solution Approach 1:
The patent makes the motor shaft serve multiple functions: it drives the motor for pumping/compression and simultaneously drives the generator for local power generation, eliminating the need for separate dedicated power cables
Solution Approach 2:
The patent merges the power transmission function into the existing motor control conductors and combines local power generation with the motor system, reducing the overall number of cables and connectors required
3Ease of operation
If power is supplied from surface location over long distances, then downhole tools can operate, but the distance and harsh conditions cause power loss and reliability issues
Solution Approach 1:
The patent implements preliminary power generation at the downhole location by coupling a generator to the motor shaft, so power is generated locally before being needed by the downhole tool components, eliminating transmission losses
Solution Approach 2:
The downhole system serves itself by generating its own power locally through the generator-motor coupling, reducing dependence on external surface-based power sources and long-distance transmission
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 solution enhances the reliability and availability of power for downhole tools by eliminating the need for dedicated cables and connectors, ensuring consistent power supply and reducing operational costs, while maintaining equipment integrity in harsh conditions.
Implementation Method 1
a rectifier to direct a portion of the power from the three-phase conductors to the downhole-type tool
Implementation Method 2
The voltage regulator can include a buck converter, the buck converter to provide a constant voltage output to the at least one downhole-type tool
Implementation Method 3
positioning a downhole-type electric motor in a wellbore, electrically connecting a variable speed drive to the electric motor with three-phase conductors
Data Source
AI summary
Providing power to a downhole-type tool includes positioning a downhole-type electric motor in a wellbore, electrically connecting a variable speed drive to the electric motor with three-phase conductors extending between the variable speed drive and the electric motor, where the variable speed drive controls and supplies power to the electric motor through the three-phase conductors, diverting at least a portion of a power supply from the three-phase conductors to a rectifier, and supplying, from the rectifier, the diverted portion of the power supply to at least one downhole-type tool proximate to the electric motor, the at least one downhole-type tool operable using the diverted portion of the power supply.