Downhole Spark-Gap Tool Piezoelectric Voltage Generation
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Solution Overview
Problem
Spark-gap tools in the hydrocarbon industry face limitations due to the need for high voltage, which results in significant voltage drop over long electrical conductors, making them less acceptable for permanent completions and requiring compromises in wellbore power delivery.
Innovation Solution
A spark-gap tool with a housing, electrodes, and a mandrel that uses transductive elements, such as piezoelectric elements, to generate voltage through mechanical distortion, eliminating the need for high-voltage transmission from the surface by creating a voltage potential through axial and rotational movement of the mandrel within the housing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high voltage is supplied from surface through electrical conductors to the spark-gap tool, then the spark-gap tool can function acceptably, but the voltage drop over long conductors increases and requires greater surface supply voltage
Solution Approach 1:
The patent extracts the voltage generation function from the surface supply system and relocates it to the downhole environment. The spark-gap tool generates its own voltage through mechanical distortion of transductive elements, eliminating the need for long electrical conductors to transmit high voltage from the surface, thereby resolving the voltage drop issue.
Solution Approach 2:
The spark-gap tool becomes self-powered by converting mechanical energy from wellbore operations (such as mandrel movement) directly into electrical voltage through transductive elements. This self-service capability eliminates dependence on surface supply voltage and resolves the energy loss problem over long conductors.
2Reliability
If greater voltage is used from surface supply to compensate for conductor length, then acceptable arc can be produced at spark-gap tool, but rig operator comfort and acceptance decrease
Solution Approach 1:
The patent removes the high-voltage surface supply requirement from the system. By generating voltage locally at the spark-gap tool through mechanical distortion of transductive elements, the system eliminates the need for operators to deal with high-voltage surface supply systems, thereby improving ease of operation while maintaining arc production capability.
3Power
If electrical conductors are used to deliver power to spark-gap tool, then voltage can be transmitted, but the wellbore requires compromises in power delivery accommodation
Solution Approach 1:
The patent extracts the power delivery requirement from the wellbore electrical conductor system. By generating voltage locally at the spark-gap tool using mechanical energy conversion through transductive elements, the system eliminates the need for complex wellbore power delivery accommodation, thereby reducing device complexity.
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 allows for efficient in-situ voltage generation near the spark-gap electrodes, reducing voltage loss and enabling the tool to function effectively without the need for high surface voltages, thereby increasing its usability in the hydrocarbon industry.
Implementation Method 1
transductive element(s) located at one of the housing and the mandrel, and a force transmission configuration located at the other of the housing, and the mandrel, the initiator, upon relative movement between the housing and the mandrel, causing a physical distortion of one or more transductive elements, whereby an electrical potential is generated by the one or more transductive elements
Data Source
AI summary
A spark-gap tool includes a plurality of electrodes, a mandrel, transductive element(s), and a force transmission configuration. Upon relative movement between components a physical distortion of one or more transductive elements occurs, whereby an electrical potential is generated. A method for powering the spark-gap tool is by physically distorting one or more transductive elements by moving components axially and/or rotationally. A method for treating a borehole is by physically distorting one or more transductive elements thereby creating sufficient voltage potential to cause an arc of selected magnitude across a spark-gap in the tool. A downhole power generation arrangement includes a first member and a second member that are movable and a piezoelectric element on one of the first member and the second member and in force transmissive communication with the other of the first member and the second member.