Azimuthal Transmitter Array for Eccentering-Resistant Cement Bonding

Solution Overview

Problem

Current downhole acoustic tools for evaluating cement bonding quality and formation elastic properties are limited by tool eccentering, low measurement frequency, and inability to provide accurate azimuthal coverage, leading to inaccurate interpretations of cement bonding and formation properties.

Innovation Solution

The use of a downhole tool with an array of azimuthally distributed transmitters and receivers, allowing for both axial and angle path measurements, which enables comprehensive azimuthal coverage and correction for eccentering effects by processing travel times of casing amplitudes, thereby improving the accuracy of cement bonding and formation property evaluations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional single-transmitter acoustic logging is used, then the tool structure is simple, but measurement precision deteriorates due to tool eccentering sensitivity

Engineering Contradiction:

Improvecement bonding evaluation accuracyVSAvoidtransmitter and receiver array configuration

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The acoustic logging tool is segmented into multiple transmitters and receivers distributed around the tool body. Each transmitter-receiver pair operates independently to provide multiple measurement paths, reducing sensitivity to tool eccentering while maintaining structural feasibility through modular arrangement

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Multiple transmitter and receiver elements are combined into a single integrated tool assembly. The merged system processes signals from all elements simultaneously, providing comprehensive azimuthal coverage and enabling accurate cement bonding evaluation regardless of tool position within the casing

Inventive Principle:

Principle #5Merging (Combining)

2Measurement precision

If low frequency acoustic signals are used, then the tool can penetrate deeper into the formation, but spatial resolution deteriorates

Engineering Contradiction:

Improvespatial resolution of formation propertiesVSAvoidacoustic signal frequency range

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The acoustic measurement system provides local quality enhancement by using multiple closely-spaced receivers to capture high-frequency signal components. This localized high-frequency measurement capability improves spatial resolution of formation properties while the overall system maintains deep penetration through appropriate frequency selection

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The system transitions from single-dimension depth penetration to multi-dimensional measurement by incorporating azimuthal distribution of transmitters and receivers. This dimensional expansion enables simultaneous achievement of deep penetration and high spatial resolution through complementary measurement paths

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Adaptability or versatility

If a single transmitter and receiver array is used, then the device complexity is low, but azimuthal coverage deteriorates requiring tool rotation

Engineering Contradiction:

Improveazimuthal coverage capabilityVSAvoidmultiple transmitter and receiver arrays

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The acoustic logging tool is segmented into multiple transmitters and receivers distributed around the tool body. Each transmitter-receiver pair operates independently to provide multiple measurement paths, reducing sensitivity to tool eccentering while maintaining structural feasibility through modular arrangement

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The multiple transmitter and receiver elements serve universal functions of acoustic signal generation and detection across all azimuthal directions. This multi-functional arrangement eliminates the need for tool rotation while providing complete 360-degree azimuthal coverage for cement bonding evaluation

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Measurement precision

If high frequency acoustic signals are used, then spatial resolution improves, but measurement reliability deteriorates due to increased eccentering impact

Engineering Contradiction:

Improvespatial resolutionVSAvoidmeasurement accuracy under eccentering conditions

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

Multiple transmitter and receiver elements are combined into a single integrated tool assembly. The merged system processes signals from all elements simultaneously, providing comprehensive azimuthal coverage and enabling accurate cement bonding evaluation regardless of tool position within the casing

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The system uses feedback from multiple receiver elements to detect and compensate for tool eccentering effects. By analyzing signal variations across the distributed receiver array, the system can identify eccentering conditions and adjust measurements to maintain reliability at high frequencies

Inventive Principle:

Principle #23Feedback

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 approach enhances the spatial resolution and accuracy of cement bonding and formation property measurements, providing more reliable data without the need for physical tool rotation, and effectively addresses the limitations of existing technologies.

Implementation Method 1

transmitting an acoustic signal from a transmitter of a downhole tool positioned within a wellbore

Methodology Applied

Scientific EffectAcoustic wave propagation: Sound

Implementation Method 2

sensing an attribute of the acoustic signal with each of multiple receivers of the downhole tool

Methodology Applied

Scientific EffectAcoustic detection: Sound

Data Source

PatentUS10585202B2Acoustic sensing with azimuthally distributed transmitters and receivers

Publication Date: 2020.03.10 SCHLUMBERGER TECH CORP

AI summary

A downhole tool having a transmitter array with azimuthally spaced transmitters and receiver arrays with azimuthally spaced receivers. Methods of operation include transmitting an acoustic signal from an individual one of the transmitters, sensing an attribute of the acoustic signal with the receivers, and evaluating a characteristic of a portion of a downhole feature based on response signals generated by the first and second receivers. Each response signal is indicative of the acoustic signal attribute sensed by the corresponding receivers. This is repeated with different individual ones of the transmitters and receivers until the evaluated portions of the downhole feature collectively extend around a wellbore.