Behind-Casing Power Harvester for Downhole Sensors
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Solution Overview
Problem
Existing methods for powering downhole components behind casing in oil and gas operations face challenges in delivering electrical power over extended periods without significant modification to downhole hardware, as these components are difficult to access once well construction is completed.
Innovation Solution
A system that induces an electrical current to flow within a casing, allowing it to escape radially into the formation, creating a potential difference that is harnessed by a power harvester to store and supply power to downhole components, utilizing the resistance of the formation and casing to generate voltage for power delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If behind-casing sensors are placed behind casing during well construction, then sensor placement is achieved, but access to sensors becomes difficult after well construction is completed
Solution Approach 1:
A power delivery system with surface-accessible components serves as an intermediary between the surface equipment and the behind-casing sensors. The system includes a power source, power delivery conductor, and power harvester that can be accessed from the surface through the casing, enabling power delivery to sensors without requiring direct physical access to the sensors themselves behind the casing.
2Duration of action of stationary object
If electrical power is delivered to behind-casing sensors over extended operational life, then continuous sensor operation is achieved, but significant modification to downhole hardware is required
Solution Approach 1:
The power delivery system is designed to serve multiple functions: it can power various types of downhole components (sensors, heaters, other devices) behind the casing, and can be used in different well construction scenarios. The system includes a universal power source and power delivery mechanism that can accommodate different power requirements and component types without requiring complete redesign.
Solution Approach 2:
The system includes a power harvester positioned near the behind-casing component that can automatically harvest and store electrical power from the power delivery conductor. This self-service mechanism reduces the need for complex external power management and minimizes hardware modifications by using the existing casing and formation as part of the power delivery pathway.
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
Enables the powering of downhole components over extended periods without substantial modification to conventional downhole hardware, ensuring continuous operation of sensors and other equipment by efficiently harvesting and storing electrical power from induced potential differences.
Implementation Method 1
inducing an electrical current to flow in the casing; permitting the electrical current to flow out of the casing to create a first potential difference
Implementation Method 2
creating a potential difference that is harnessed by a power harvester to store and supply power to downhole components, utilizing the resistance of the formation and casing to generate voltage for power delivery
Data Source
AI summary
A system and method according to which a downhole component positioned behind a casing is powered, the casing extending within an oil and gas wellbore that traverses a subterranean formation. Powering the downhole component may include inducing an electrical current to flow in the casing; permitting the electrical current to flow out of the casing to create a first potential difference between a first point and a second point spaced therefrom, the first and second points being located behind the casing; utilizing the first potential difference to store electrical power; and supplying the stored electrical power to the downhole component positioned behind the casing to thereby power the downhole component. The system may include a power source in electrical communication with the casing; a power harvester positioned behind the casing and in electrical communication with the downhole component; and a current return unit in electrical communication with the power source.