Downhole Acoustic Measurement Signal Time Compression

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Downhole acoustic measurement techniques, such as CBL, face challenges in achieving reliable acoustic signal transmission due to the high acoustic impedance of metallic casings and production tubing, leading to reduced signal strength and increased costs for extracting and reinserting measurement tools.

Innovation Solution

Implementing signal time compression techniques by generating reverse time sequence signals and using frequency chirp processing to enhance the signal-to-noise ratio, focusing acoustic energy at the casing-cement interface, and employing multiple acoustic sources to increase signal amplitude and measurement sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional acoustic measurement techniques are used through metallic casings and production tubing, then the measurement can be conducted without tool extraction, but the signal-to-noise ratio is reduced due to high acoustic impedance

Engineering Contradiction:

Improvesignal-to-noise ratioVSAvoidacoustic impedance of metallic casings

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by transforming the acoustic source signal from a simple impulse to a coded waveform (e.g., chirp signal with linear frequency modulation). This parameter transformation of the signal allows for enhanced signal-to-noise ratio through correlation processing, overcoming the signal degradation caused by metallic casings and production tubing.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent implements preliminary action by pre-processing the acoustic source signal with specific waveform coding (such as chirp signals) before transmission. This preliminary signal preparation enables subsequent correlation processing to compress the signal energy and enhance the signal-to-noise ratio, addressing the harmful acoustic impedance effects in advance.

Inventive Principle:

Principle #10Preliminary action

2Measurement precision

If production tubing is extracted to perform acoustic testing, then measurement sensitivity is improved, but the procedure becomes time-consuming and expensive

Engineering Contradiction:

Improvemeasurement sensitivityVSAvoidoperational efficiency

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The patent converts the harmful effect of production tubing (which attenuates acoustic signals) into a beneficial situation by developing signal processing techniques that can extract meaningful measurements through the tubing. The correlation processing of coded waveforms allows the system to overcome the tubing's acoustic impedance and achieve adequate measurement sensitivity without extraction.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent replaces the mechanical approach of physically extracting production tubing with a signal processing approach. Instead of mechanically removing the tubing to improve measurements, the system uses coded waveform transmission and correlation processing to achieve the same measurement sensitivity improvement through signal manipulation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Power

If simple acoustic impulse signals are transmitted, then the measurement process is simple, but the signal amplitude is insufficient for reliable cement bonding evaluation

Engineering Contradiction:

Improvesignal amplitudeVSAvoidsignal processing complexity

Core Design Contradiction:

PowerVSDevice complexity

Solution Approach 1:

The patent applies periodic action by using coded waveforms such as chirp signals that sweep through a range of frequencies over a defined time period. This periodic frequency modulation allows the signal to accumulate energy across multiple cycles, increasing the effective signal amplitude while enabling correlation processing to compress and enhance the returned signal for reliable cement bonding evaluation.

Inventive Principle:

Principle #19Periodic action

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

Improves the signal-to-noise ratio and measurement sensitivity, enabling more effective acoustic evaluation of cement bonding and material properties without the need for extensive tool extraction and reinsertion, thus reducing costs and increasing efficiency.

Implementation Method 1

an acoustic source and one or more acoustic receivers deployed within a borehole to generate and detect acoustic echoes

Methodology Applied

Scientific EffectAcoustic wave propagation: Sound

Implementation Method 2

acoustic measurement data that may be interpreted to determine bonding integrity

Methodology Applied

Scientific EffectAcoustic reflection: Reflection

Data Source

PatentUS11650346B2Downhole acoustic measurement

Publication Date: 2023.05.16 HALLIBURTON ENERGY SERVICES INC

AI summary

A method comprises positioning a receiver in a borehole and determining an offset acoustic waveform at a target point. The method includes generating a reverse time sequence waveform of the determined offset acoustic waveform and generating, by a transmitter, an acoustic pulse based on the reverse time sequence waveform. The method includes detecting, by the receiver, an acoustic response to the acoustic pulse.