Rock Matrix Permittivity Determination Using Matching Liquid

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Solution Overview

Problem

Existing methods for determining the permittivity of rock matrices are hindered by the difficulty in isolating the permittivity of the rock matrix from saturated rock measurements, as the contribution of pore space cannot be accurately determined, leading to errors in hydrocarbon volume estimation and mobility prediction.

Innovation Solution

A method involving a matching liquid with temperature-dependent permittivity is used to saturate a rock sample, allowing for differential permittivity measurements to isolate the rock matrix permittivity by matching the liquid's permittivity to the sample's, thereby eliminating the need for mixing rules and porosity knowledge.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If mixing rules are used to calculate rock matrix permittivity from saturated rock measurements, then permittivity values can be obtained, but large errors are introduced due to unknown validity and varying assumptions of different mixing rules

Engineering Contradiction:

Improverock matrix permittivity determination accuracyVSAvoidmixing rule validity

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

A matching liquid with temperature-dependent permittivity is introduced as an intermediary medium to saturate the rock sample. By adjusting the liquid's permittivity to match the rock matrix permittivity at a specific temperature, the liquid acts as a mediator that eliminates the need for mixing rules. The matching liquid allows direct measurement of rock matrix permittivity by nullifying the pore space contribution through permittivity matching.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The permittivity of the matching liquid is changed by varying its temperature, since liquid permittivity is temperature-dependent. This parameter change allows the liquid permittivity to be adjusted until it matches the rock matrix permittivity, enabling accurate determination without relying on uncertain mixing rule assumptions.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If saturated rock permittivity measurements are used to determine rock matrix permittivity, then measurements can be performed, but the contribution of pore space cannot be accurately isolated leading to measurement errors

Engineering Contradiction:

Improverock matrix permittivity measurement accuracyVSAvoidpore space contribution separation

Core Design Contradiction:

Measurement precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The matching liquid serves as an intermediary that fills the pore space and matches the permittivity of the rock matrix. This eliminates the need to separately measure and subtract pore space contributions, as the matching liquid's permittivity is equal to that of the rock matrix, making the saturated rock permittivity equal to the rock matrix permittivity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

By changing the temperature of the matching liquid, its permittivity changes accordingly. This allows the liquid permittivity to be adjusted to match the rock matrix permittivity, thereby eliminating the pore space contribution issue and enabling direct measurement of rock matrix permittivity from saturated rock measurements.

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If conventional permittivity measurement methods are used on powdered rock samples suspended in liquid, then permittivity measurements can be obtained, but the fluid saturating the pores mixes the pore effects with the measured permittivity preventing isolation of rock matrix permittivity

Engineering Contradiction:

Improverock matrix permittivity isolationVSAvoidpore space permittivity contribution

Core Design Contradiction:

Measurement precisionVSLoss of information

Solution Approach 1:

The matching liquid acts as an intermediary medium that suspends the powdered rock samples. By matching the liquid's permittivity to the rock matrix permittivity, the liquid eliminates the pore space contribution to the measurement, allowing direct determination of rock matrix permittivity without information loss.

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

This approach enables accurate determination of rock matrix permittivity without relying on mixing rules or volume fraction measurements, reducing errors and improving hydrocarbon estimation and mobility prediction.

Implementation Method 1

Methodology Applied

Scientific EffectPermittivity matching: Dielectric Permittivity

Implementation Method 2

the permittivity of the porous sample may be determined by saturating the rock sample in the matching liquid, measuring the permittivity of the sample as a function of temperature, and determining the temperature and hence the liquid permittivity that matches the permittivity of the porous sample

Methodology Applied

Scientific EffectTemperature-dependent permittivity: Dielectric Permittivity

Data Source

PatentUS9366613B2Matrix permitivity determination

Publication Date: 2016.06.14 SCHLUMBERGER TECH CORP

AI summary

A method and system for determining a rock matrix dielectric permittivity. The method and system use a matching liquid with a temperature dependant permittivity. The matching liquid may be used in an automated and/or downhole system for measuring matrix dielectric permittivity of rock formations.