Full Digital Acoustic Logging Transducer Array

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Solution Overview

Problem

Acoustic logging while drilling instruments face challenges in maintaining a high signal-to-noise ratio due to the use of analog signals, which are prone to noise interference during transmission, especially in harsh drilling environments.

Innovation Solution

A full-digital device for the receiving transducer array is introduced, featuring a non-oil-filled rubber encapsulation and modular design with pre-amplification, filtering, gain control, and analog-to-digital conversion, allowing for digital signal processing and improved noise immunity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the acquisition circuit is placed in an inner cavity of the instrument at a distance of 30-50 cm from the receiving piezoelectric ceramic wafer, then the ceramic wafer arrangement structure is simple, but the signal is extremely easy to influence by external environment, noise is increased, and thus the signal-to-noise ratio of the signal is reduced

Engineering Contradiction:

Improveceramic wafer arrangement structureVSAvoidsignal-to-noise ratio

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The device is divided into two independent modules: a receiving module containing the piezoelectric ceramic wafer and a processing module containing the acquisition circuit. These modules are connected via a shielded cable, allowing the simple ceramic arrangement to be maintained while isolating the signal processing from environmental noise in the wellbore environment.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A shielded cable acts as an intermediary between the receiving module and processing module, transmitting the weak electrical signals from the piezoelectric ceramic while protecting them from external electromagnetic interference and noise in the harsh wellbore environment.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If analog signals are used for transmission without nearby digitalization, then the installation process is simpler, but the signal-to-noise ratios of the signals are poor and noise immunity is relatively poor

Engineering Contradiction:

Improveinstallation processVSAvoidsignal-to-noise ratio

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

Analog-to-digital conversion is performed preliminarily in the processing module before the signals are transmitted through the shielded cable to the surface. This preliminary digitalization ensures that only digital signals, which are immune to noise during transmission, need to be handled during installation and operation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system replaces analog signal transmission with digital signal transmission. By converting analog signals to digital signals at the source, the system eliminates the problems of noise and interference associated with analog transmission over long distances in harsh environments.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If all modules are placed in an oil-filled environment for nearby digitalized sampling, then the signal-to-noise ratios of the signals are improved, but the installation process and digitalization of the modules are complex and cannot be realized

Engineering Contradiction:

Improvesignal-to-noise ratioVSAvoidinstallation process and module digitalization

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system segments the device into a receiving module that can operate in the wellbore environment and a processing module that performs digital conversion. This segmentation avoids the need for complex oil-filled environments while still achieving nearby digitalization through the shielded cable connection.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The shielded cable serves as an intermediary that enables digital signal transmission from the receiving module to the processing module without requiring the entire system to be placed in a complex oil-filled environment, thereby simplifying installation while maintaining signal quality.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

The solution enhances signal consistency and noise resistance, simplifying installation and maintenance while maintaining performance in severe drilling conditions.

Implementation Method 1

The acoustic signals received by the receiving transducers are converted into weak current signals through piezoelectric ceramic wafers

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentUS11359485B2Full digital device of receiving transducer array of acoustic logging while drilling instrument

Publication Date: 2022.06.14 INSTITUTE OF GEOLOGY AND GEOPHYSICS CHINESE ACADEMY OF SCIENCES

AI summary

An acoustic while drilling receiving transducer array adopts a full-digital structure and a non-oil-filled rubber encapsulation arrangement mode, and the full-digital device of the acoustic while drilling receiving transducer array includes first modules, configured to carry out acoustic-to-electric conversion on weakly received acoustic signals of strata; second modules, configured to carry out amplification, filtering, gain control and digital-to-analog conversion on the weakly received acoustic signals; and a third module, configured to control interfaces of the device and convert external input and output signals.