Downhole Tool Actuation via Tonal Frequency Signals

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Solution Overview

Problem

Downhole tools in wellbores face issues with accidental actuation due to formation characteristics and signal sensitivity, particularly in systems using voltage polarity switching, which can lead to unintended activation of explosive devices.

Innovation Solution

Implementing a downhole tool system that uses tonal signals with specific frequencies to actuate tools, where each tool is uniquely associated with a reference frequency, reducing accidental actuation and signal decoding errors, and allowing power transmission only to intended tools.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If voltage polarity switching is used to actuate downhole tools, then multiple tools can be actuated in sequence, but accidental actuation occurs due to formation characteristics and signal sensitivity

Engineering Contradiction:

Improvetool actuation capabilityVSAvoidaccidental actuation prevention

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent changes the signal parameter from voltage polarity switching to tonal frequency signals. Each downhole tool is assigned a unique reference frequency, and the system transmits tonal signals at different frequencies to actuate specific tools. This parameter change eliminates accidental actuation because tools only respond to their designated frequency, preventing misactivation due to formation characteristics or signal interference.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical voltage polarity switching system with an acoustic/tonal signal system. Instead of using mechanical pressure-actuated switches that can shift accidentally, the system uses tonal signals that are transmitted through the wireline and detected by piezoelectric elements in each tool. This substitution eliminates the mechanical switching reliability issues while maintaining the ability to actuate multiple tools in sequence.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If pressure-actuated mechanical switching switches are used, then polarity can be switched between tools, but the switch may shift accidentally due to formation characteristics

Engineering Contradiction:

Improvepolarity switchingVSAvoidswitch stability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent eliminates the mechanical pressure-actuated switching system entirely and replaces it with a tonal signal-based control system. Each tool has a unique reference frequency encoded in its controller, and the system transmits tonal signals to activate specific tools. This removes the mechanical switch that was prone to accidental shifting, while still enabling controlled polarity switching through frequency-based addressing.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the control parameter from mechanical pressure/switch position to tonal frequency. By encoding tool identification and actuation commands in frequency parameters rather than mechanical switch states, the system achieves reliable polarity switching without the instability of pressure-actuated mechanical switches that can shift due to formation characteristics.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If multiple downhole tools are connected in series via wireline, then power and signals can be transmitted to all tools, but signal decoding errors occur due to signal level fluctuations

Engineering Contradiction:

Improvetool actuation capabilityVSAvoidsignal decoding accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent changes the signal transmission parameter from voltage polarity to tonal frequency modulation. Each tool is assigned a unique reference frequency, and the system transmits tonal signals that modulate the wireline signal. This frequency-based approach is more resistant to signal level fluctuations because the frequency information remains stable even when amplitude varies, reducing signal decoding errors while maintaining the ability to communicate with multiple tools.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the voltage-polarity-based signaling system with a tonal signal system that uses frequency modulation. This substitution provides better signal robustness against level fluctuations, as frequency detection is less sensitive to amplitude variations than voltage polarity detection. The piezoelectric elements in each tool detect the tonal frequency rather than voltage polarity, improving decoding accuracy in the presence of signal fluctuations.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS8451137B2Actuating downhole devices in a wellbore

Publication Date: 2013.05.28 HALLIBURTON ENERGY SERVICES INC

AI summary

A downhole tool system includes a first downhole tool and a second downhole tool. The first downhole tool includes a first controller operable to receive an actuation signal including a tone. The first controller actuates the first downhole tool if the tone is a first specified frequency and changes the first downhole tool to communicate the actuation signal to the second downhole tool if first downhole tool is not actuated in response to the actuation signal. A second downhole tool includes a second controller operable to receive the actuation signal. The second controller actuates the second downhole tool if the tone is a second specified frequency. The second frequency is different from the first frequency.