Estimating Water Saturation via Interfacial Polarization Modeling

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Solution Overview

Problem

Conventional electromagnetic measurements in geological environments neglect electrodiffusion and electrochemical effects at interfaces, leading to inaccurate interpretations and impacting the economic viability of hydrocarbon recovery.

Innovation Solution

A method to estimate water saturation in electromagnetic measurements by quantifying interfacial polarization effects using analytical and numerical models, including a dipole moment analysis and effective medium formulation, to accurately determine complex conductivity and petrophysical properties, accounting for conductive minerals and fractures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional electromagnetic measurements are used in heterogeneous geological materials, then the measurement process is simple, but the interpretation accuracy deteriorates due to neglecting electrodiffusion and electrochemical effects at interfaces

Engineering Contradiction:

Improveinterpretation accuracyVSAvoidmeasurement model complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by incorporating electrodiffusion and electrochemical effects into the electromagnetic measurement model. This involves modifying the conventional measurement approach to include additional physical parameters related to interfacial phenomena, thereby improving interpretation accuracy while managing the increased model complexity through systematic parameter integration

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses effective medium theory as an intermediary approach to bridge the gap between simple conventional measurements and complex interfacial effects. By introducing effective conductivity parameters that account for electrodiffusion and electrochemical phenomena, the method improves measurement accuracy without requiring direct observation of every interface, thus balancing precision with practical complexity

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If petrophysically-adverse alterations are present in EM measurements, then the measurement process remains unchanged, but the accuracy of water saturation estimation deteriorates

Engineering Contradiction:

Improvewater saturation estimation accuracyVSAvoidconductive mineral interference

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent extracts and isolates the effects of conductive minerals (pyrite, graphitic-precursors, magnetite) from the overall electromagnetic response. By identifying and separating these adverse alterations, the method can then remove or correct their influence on water saturation estimation, thereby improving measurement precision while addressing the harmful interference from conductive minerals

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent converts the harmful effect of conductive minerals by using their characteristic electromagnetic signatures as diagnostic indicators. Instead of merely treating them as noise, the method leverages the specific frequency-dependent responses of pyrite, graphitic-precursors, and magnetite to identify and correct for their presence, transforming the interference into useful information for improved water saturation estimation

Inventive Principle:

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

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 provides accurate electrical property estimation and improved resistivity interpretation, enhancing the accuracy of hydrocarbon recovery assessments by accounting for interfacial polarization effects in heterogeneous geological formations.

Implementation Method 1

quantifying interfacial polarization effects using analytical and numerical models

Methodology Applied

Scientific EffectInterfacial polarization: Polarisation

Implementation Method 2

electrodiffusion and electrochemical effects occurring at interfaces

Methodology Applied

Scientific EffectElectrodiffusion: Diffusion

Implementation Method 3

electrodiffusion and electrochemical effects occurring at interfaces

Methodology Applied

Scientific EffectElectrochemical effects:

Implementation Method 4

including a dipole moment analysis and effective medium formulation

Methodology Applied

Scientific EffectDipole moment:

Implementation Method 5

including a dipole moment analysis and effective medium formulation, to accurately determine complex conductivity

Methodology Applied

Scientific EffectEffective medium theory:

Data Source

PatentUS10330618B2Method to estimate water saturation in electromagnetic measurements

Publication Date: 2019.06.25 SCHLUMBERGER TECH CORP

AI summary

A method to estimate water saturation in electromagnetic measurements includes making an electromagnetic measurement and performing at least one of (a) creating an analytical forward model of the EM measurement, (b) creating a numerical finite difference forward model of the EM measurement, and (c) performing an inversion. The method also includes removing at least one petrophysically-adverse alteration of EM measurements in the frequency range from 1 Hz to 100 MHz. A petrophysically-adverse alteration is due to the presence of at least one of the following: pyrite, graphitic-precursors, magnetite, and other conductive minerals.