NMR Echo Processing Matched Filter for Well Logging Precision

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Solution Overview

Problem

Current NMR echo data processing techniques face challenges in accurately filtering and interpreting data from NMR logging tools used in well logging, particularly in real-time applications, due to inhomogeneous magnetic fields and noise interference, which affects the precision of formation porosity and fluid property measurements.

Innovation Solution

The implementation of a matched filter module in the NMR echo processing system, which is designed to match the response of the NMR tool, incorporating non-NMR measurements like temperature and salinity, to filter and process NMR echo data sets effectively, improving signal-to-noise ratio and data accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional NMR echo data processing techniques are used, then the processing can be performed with simple methods, but the measurement precision and reliability of formation porosity and fluid property measurements deteriorate due to inhomogeneous magnetic fields and noise interference

Engineering Contradiction:

Improveformation porosity and fluid property measurementsVSAvoidNMR echo processing system

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The NMR echo processing system is segmented into distinct functional modules: a matched filter module that processes NMR echo data using a filter matched to the NMR tool response, and an inversion module that performs formation property calculations. This segmentation allows each module to be optimized independently, improving measurement precision while managing system complexity through modular architecture.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A matched filter is introduced as an intermediary component between the NMR tool and the inversion module. This filter is specifically designed to match the impulse response of the NMR tool, thereby optimizing the signal-to-noise ratio and compensating for inhomogeneous magnetic field effects before the data reaches the inversion module, thus improving measurement precision without requiring fundamental changes to the NMR tool itself.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If real-time processing is implemented to meet increasing demand for information while drilling, then productivity improves, but measurement precision deteriorates due to noise interference and inhomogeneous fields

Engineering Contradiction:

Improvereal-time information processingVSAvoidformation evaluation measurements

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The matched filter is applied as a preliminary processing step before inversion and formation property calculation. By pre-processing the NMR echo data with a filter matched to the tool response, the signal-to-noise ratio is optimized in advance, ensuring that real-time processing maintains high measurement precision without requiring post-processing corrections that would delay results.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system incorporates feedback mechanisms where the matched filter is designed based on the known impulse response of the specific NMR tool being used. This feedback loop ensures that the processing algorithm is continuously optimized for the actual tool performance, maintaining measurement precision in real-time applications despite variations in noise levels and field conditions.

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 accuracy and reliability of NMR echo data processing, leading to improved formation porosity determination and fluid property measurements, even in challenging drilling environments with inhomogeneous fields and noise interference.

Implementation Method 1

nuclear magnetic resonance (NMR) tools... measure, among other things, relaxation times... of formation fluids

Methodology Applied

Scientific EffectNuclear magnetic resonance:

Implementation Method 2

an NMR echo processing module including a filter matched to a response of the NMR tool to output a filtered NMR echo data set from the NMR echo data set

Methodology Applied

Scientific EffectSignal filtering: Filter (electronic)

Data Source

PatentUS10088594B2Methods and apparatuses for echo processing of nuclear magnetic resonance (NMR) data

Publication Date: 2018.10.02 SCHLUMBERGER TECH CORP

AI summary

A nuclear magnetic resonance (NMR) system includes a transmitter of an NMR tool to output a magnetic field pulse into a zone of interest, a receiver of the NMR tool to output an NMR echo data set produced from an interaction of the magnetic field pulse and the zone of interest, and an NMR echo processing module including a filter matched to a response of the NMR tool to output a filtered NMR echo data set from the NMR echo data set, wherein the filter is matched to an echo shape of the NMR echo data, is matched to an average of a selected signal spectra of the NMR echo data set, or dynamically changes in response to a measurement.