Helium Diffusion Coefficient Measurement in Natural Gas

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Solution Overview

Problem

There is currently no systematic method or supporting experimental device to quantitatively characterize the diffusion behavior of helium in helium-bearing natural gas, limiting the understanding of reservoir formation theory and resource potential assessment.

Innovation Solution

A device and method involving a diffusion system with upstream and downstream diffusion chambers, a true triaxial apparatus, and a gas sampling and analysis system to simulate helium diffusion in helium-bearing natural gas, using argon and helium-bearing gas to calculate the effective diffusion coefficient of helium through rock cores, employing chromatographic analysis and pressure difference balancing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If no systematic experimental device is used, then the understanding of reservoir formation theory is limited, but the complexity of the device is high

Engineering Contradiction:

Improvequantitative characterization of helium diffusion behaviorVSAvoidsystematic experimental device structure

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The experimental device is divided into multiple independent functional modules: diffusion chamber, true triaxial stress system, temperature control system, and gas sampling system. Each module performs a specific function, allowing the complex measurement task to be broken down into manageable components that can be independently optimized and maintained.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The true triaxial apparatus serves multiple functions simultaneously: it applies controlled stress to the rock core, maintains formation temperature conditions, and provides the structural framework for the diffusion experiment. This multi-functionality reduces the need for separate dedicated devices for each function.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Measurement precision

If helium diffusion is simulated in helium-bearing natural gas, then the measurement accuracy is improved, but the time required for experimentation increases

Engineering Contradiction:

Improveeffective diffusion coefficient measurementVSAvoiddiffusion experimentation duration

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The rock core is pre-treated and saturated with helium-bearing natural gas before the diffusion experiment begins. The true triaxial stress conditions are applied in advance to establish the formation-like environment. This preliminary preparation ensures that when the diffusion measurement starts, the system is already in the correct state, reducing the total experimentation time.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The gas sampling system continuously monitors the diffusion process without interrupting the experimental conditions. The chromatographic analyzer provides real-time data on gas composition changes, allowing the diffusion coefficient to be calculated from continuous measurements rather than requiring multiple discrete sampling intervals.

Inventive Principle:

Principle #20Continuity of useful action

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 simulation and measurement of helium diffusion in geological environments, providing a comprehensive method to quantify helium diffusion behavior and calculate its effective diffusion coefficient in helium-bearing natural gas.

Implementation Method 1

helium has the strongest diffusion ability. Helium diffusion is one of the main causes of helium reservoir damage.

Methodology Applied

Scientific EffectDiffusion: Diffusion

Implementation Method 2

the chromatographic analyzer is configured to analyze gas composition in the upstream gas sample retention chamber and the downstream gas sample retention chamber

Methodology Applied

Scientific EffectChromatography: Chromatography

Implementation Method 3

the true triaxial apparatus is configured to accommodate a rock core, apply a load to the rock core, and simulate a formation temperature

Methodology Applied

Scientific EffectMechanical stress: Mechanical Force

Implementation Method 4

an initial state of the upstream gas sample retention chamber and the downstream gas sample retention chamber is a vacuum state for convenience of gas sampling

Methodology Applied

Scientific EffectVacuum: Vacuum

Data Source

PatentUS11841304B1Device and method for testing effective diffusion coefficient of helium in helium-bearing natural gas

Publication Date: 2023.12.12 PEKING UNIV

AI summary

A device and method for testing an effective diffusion coefficient of helium in helium-bearing natural gas solves the problem that there is currently no systematic method or supporting experimental device to quantitatively characterize the diffusion behavior of helium in helium-bearing natural gas. The device includes a diffusion system and a gas sampling and analysis system. The diffusion system includes an upstream diffusion chamber, a downstream diffusion chamber, and a true triaxial apparatus, and is configured to simulate a gas diffusion process. The gas sampling and analysis system includes an upstream gas sample retention chamber, a downstream gas sample retention chamber, and a chromatographic analyzer, and is configured to sample a diffusing gas and analyze composition of the gas. By performing diffusion process simulation, gas sampling and analysis, and data calculation and fitting, the effective diffusion coefficient of helium in the helium-bearing natural gas is finally acquired.