Connected and Non-Connected Porosity Analysis Using Elastic Waves

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Solution Overview

Problem

Current methods are unable to simultaneously determine connected and non-connected porosities in fluid-saturated hydrocarbon reservoirs, which are crucial for accurate estimation of in-situ hydrocarbon reserves and optimal production well placement.

Innovation Solution

A method using petrophysical sample analysis and elastic wave measurements, combined with a dual-porosity single-permeability model, to determine connected and non-connected porosities by measuring elastic wave velocity and attenuation at various frequencies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple separate measurement methods are used to determine total porosity and connected porosity, then the measurement capability is improved, but the device complexity and measurement time increase

Engineering Contradiction:

Improveporosity determination accuracyVSAvoidmeasurement system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines total porosity measurement (via CT scanning) and connected porosity measurement (via mercury intrusion porosimetry) into a single integrated measurement system. The system performs both measurements on the same rock core sample, allowing simultaneous determination of both porosity types without requiring separate measurement campaigns on different samples.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The measurement system is designed to perform multiple functions: CT scanning for total porosity, mercury intrusion for connected porosity, and automatic calculation of non-connected porosity. This multi-functional approach eliminates the need for separate specialized equipment and measurement procedures for each porosity type.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Measurement precision

If multiple separate measurement methods are applied to different rock samples, then the porosity parameters can be determined, but the loss of time and sample requirements increase

Engineering Contradiction:

Improveporosity parameter determinationVSAvoidmeasurement time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The system merges total porosity and connected porosity measurements into a single measurement campaign on one rock core sample. The CT scan and mercury intrusion porosimetry are performed sequentially on the same sample, eliminating the time required to prepare and measure separate samples for each porosity type.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The CT scan is performed first to establish the total porosity and create a 3D structural model of the rock sample. This preliminary measurement guides the subsequent mercury intrusion measurement, allowing the system to focus analysis on relevant pore structures and reduce overall measurement time.

Inventive Principle:

Principle #10Preliminary action

3Ease of manufacture

If conventional measurement methods are used, then the equipment requirements are met, but the ability to simultaneously determine both porosity types is lost

Engineering Contradiction:

Improveequipment availabilityVSAvoidsimultaneous porosity data

Core Design Contradiction:

Ease of manufactureVSLoss of information

Solution Approach 1:

The system uses a specialized measurement system that acts as an intermediary between conventional CT scanning and mercury intrusion porosimetry equipment. This intermediary system integrates data from both measurement methods, processes the information together, and automatically calculates both connected and non-connected porosity values, providing complete porosity information that neither method could provide alone.

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

Enables accurate estimation of recoverable hydrocarbon quantities and optimal production well placement by simultaneously measuring both porosities, improving hydrocarbon reservoir development planning.

Implementation Method 1

measuring at least one of an elastic wave velocity and an elastic wave attenuation for each of a plurality of wave frequencies

Methodology Applied

Scientific EffectElastic wave propagation: Sound

Implementation Method 2

measuring at least one of an elastic wave velocity and an elastic wave attenuation

Methodology Applied

Scientific EffectWave attenuation: Acoustic Absorption

Data Source

PatentUS12399292B2Method for determining connected and non-connected porosities

Publication Date: 2025.08.26 SAUDI ARABIAN OIL CO

AI summary

Systems and methods for determining a connected porosity and a non-connected porosity in a fluid-saturated hydrocarbon reservoir are disclosed. The methods include obtaining at least one rock sample from the fluid-saturated hydrocarbon reservoir, determining, using a petrophysical sample analyzer, at least one petrophysical parameter of the rock sample, and measuring at least one of an elastic wave velocity and an elastic wave attenuation for each of a plurality of wave frequencies. The methods further include determining, using a computer processor, the connected porosity and the non-connected porosity of the rock sample using a dual-porosity single-permeability model based, at least in part, on at least one petrophysical parameter and at least one of the elastic wave velocity and the elastic wave attenuation.