In-situ Methane Partial Pressure Measurement for Coal Bed Gas Factors

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Solution Overview

Problem

Traditional methods for determining coal bed natural gas production factors, such as critical desorption pressure and gas content, are expensive, time-consuming, and prone to errors, requiring core sample retrieval and laboratory analysis.

Innovation Solution

Measuring methane partial pressure in the coal seam reservoir fluid, which correlates to critical desorption pressure, allowing for the determination of production factors like gas content, dewatering time, and other variables through direct measurement and correlation using instruments like optical spectrometers and pressure transducers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional core sample retrieval and laboratory analysis methods are used to determine production factors, then measurement precision can be achieved, but loss of time and cost increase significantly

Engineering Contradiction:

Improveproduction factors determination accuracyVSAvoidtime for core sample retrieval and lab analysis

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces mechanical core sample retrieval and laboratory analysis systems with an in-situ measurement system using optical spectrometers and pressure transducers that directly measure methane partial pressure and other parameters within the coal seam reservoir fluid, eliminating the need for physical sample transport and lab processing

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses methane partial pressure as an intermediary parameter that correlates to critical desorption pressure and other production factors, allowing indirect determination of these factors through direct in-situ measurement of the intermediary rather than direct measurement of the target parameters themselves

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If traditional core sample retrieval and laboratory analysis methods are used to determine production factors, then measurement precision can be achieved, but cost increases significantly

Engineering Contradiction:

Improveproduction factors determination accuracyVSAvoidcost of core sample retrieval and lab analysis

Core Design Contradiction:

Measurement precisionVSLoss of energy

Solution Approach 1:

The patent replaces expensive mechanical core sample retrieval operations and laboratory analysis facilities with in-situ optical and pressure measurement tools that can be deployed directly in the wellbore, significantly reducing operational costs while maintaining measurement accuracy

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The measurement system performs self-service by directly determining production factors from in-situ measurements of methane partial pressure and other reservoir fluid parameters, eliminating the need for external laboratory services and core sample handling operations

Inventive Principle:

Principle #25Self-service

3Productivity

If direct measurement of methane partial pressure is used to determine production factors, then productivity increases and time is reduced, but device complexity increases

Engineering Contradiction:

Improvespeed of production factors determinationVSAvoidcomplexity of in-situ measurement system

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the measurement system into distinct functional components: optical spectrometers for methane concentration measurement, pressure transducers for total pressure measurement, and a processing system that correlates these measurements to determine methane partial pressure and production factors, allowing each component to be optimized independently

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The measurement system is designed with multi-functionality, using the same in-situ instrumentation platform to measure multiple parameters including methane partial pressure, total pressure, temperature, and other reservoir fluid properties, reducing overall system complexity compared to dedicated systems for each measurement

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 method provides accurate and efficient determination of coal bed natural gas production factors, reducing costs and time while enhancing precision, enabling better prediction of well performance and methane reserves.

Implementation Method 1

measuring a concentration of methane or another substance indicative of the methane partial pressure

Methodology Applied

Scientific EffectAbsorption Spectroscopy: Absorption Spectroscopy

Implementation Method 2

measuring a partial pressure of methane or another substance indicative of the methane partial pressure

Methodology Applied

Scientific EffectPressure measurement:

Implementation Method 3

measuring a concentration of methane or another substance indicative of the methane partial pressure

Methodology Applied

Scientific EffectHenry's Law:

Data Source

PatentUS8640771B2Determination of coal bed natural gas production factors and a system to determine same

Publication Date: 2014.02.04 GAS SENSING TECHNOLOGY CORP

AI summary

Well fluids in coalbed natural gas reservoirs and other carbonaceous reservoirs are analyzed to determine production factors such as gas content, critical desorption pressure, and/or other reservoir and operational variables. In particular, the partial pressure of methane or a predictor substance, or a methane concentration, are measured and/or determined for the wells and production factors are determined therefrom.