Aromatic Biomarker Analysis for Source Rock Hydrocarbon Typing
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Solution Overview
Problem
Existing methods for determining hydrocarbon type in source rocks, particularly in marine and lacustrine source rocks, are limited by the inaccuracies and unsuitability of vitrinite reflectance as a thermal maturity indicator, leading to unreliable hydrocarbon type predictions.
Innovation Solution
A method involving the separation and analysis of the aromatic fraction from source rock samples using gas chromatography-mass spectrometry (GC-MS) to determine thermal maturity ratios, combined with thermal maturity indicators like Tmax and HI, to establish a thermal maturity relationship for accurate hydrocarbon type determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If vitrinite reflectance is used as a thermal maturity indicator, then the measurement process is simple, but the accuracy and reliability of hydrocarbon type determination deteriorates in marine and lacustrine source rocks
Solution Approach 1:
The patent extracts and analyzes the aromatic fraction from source rock samples using solvent extraction, then separates and quantifies specific biomarker compounds (such as dibenzothiophenes and alkylated naphthalenes) using gas chromatography-mass spectrometry. This extraction of specific chemical components provides a more accurate thermal maturity assessment than bulk vitrinite reflectance measurements, particularly for marine and lacustrine source rocks where vitrinite is absent or unreliable.
Solution Approach 2:
The patent introduces aromatic biomarkers as intermediary substances that mediate between the source rock matrix and thermal maturity assessment. These aromatic compounds serve as chemical proxies that preserve thermal history information more reliably than vitrinite in certain rock types, enabling accurate hydrocarbon type prediction through their molecular composition and abundance ratios.
2Measurement precision
If GC-MS analysis of aromatic fraction is performed, then the accuracy of thermal maturity determination is improved, but the device complexity and analysis time increase
Solution Approach 1:
The patent segments the complex source rock sample into specific aromatic fraction components through systematic solvent extraction and chromatographic separation. By dividing the analysis into discrete steps (extraction, separation, identification, quantification) and focusing on specific biomarker compounds rather than whole-rock analysis, the method achieves high precision while making the complex GC-MS process more manageable and interpretable.
3Reliability
If comprehensive thermal maturity relationships are established using multiple parameters, then the reliability of hydrocarbon type prediction is improved, but the loss of time and computational complexity increases
Solution Approach 1:
The patent transforms multiple thermal maturity parameters (including GC-MS derived aromatic biomarker ratios, vitrinite reflectance, and other geochemical measurements) into a unified thermal maturity relationship model. By changing the parameter space and establishing empirical or theoretical relationships between different indicators, the method integrates multiple data sources into a coherent framework that improves prediction reliability while reducing the time required for separate analyses.
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
Provides accurate and reliable hydrocarbon type assessment in source rocks, overcoming the limitations of vitrinite reflectance, and enabling better economic evaluation and modeling of hydrocarbon production.
Implementation Method 1
separating, measuring, and identifying responses of the aromatic fraction using gas chromatography-mass spectrometry (GC-MS)
Implementation Method 2
a ball mill to mechanically separate a source rock sample
Implementation Method 3
a pipette column to separate aromatic fraction from a source sample
Data Source
AI summary
Methods and systems for determining a hydrocarbon type for a source sample are disclosed. The method includes obtaining a thermal maturity relationship and the source sample from a geological region of interest. The method further includes separating aromatic fraction from the source sample, and separating, measuring, and identifying responses of the aromatic fraction using gas chromatography-mass spectrometry (GC-MS) and determining a thermal maturity ratio using the responses. The method still further includes determining a thermal maturity indicator using the thermal maturity ratio and the thermal maturity relationship and determining the hydrocarbon type based on the thermal maturity indicator. The system includes a ball mill, a pipette column, a GC-MS system, and a computer processor.