SY/T 5121-2021 in English

Key equipment technical indicators:

• Fourier transform infrared spectrometer: wave number range 4000-400cm⁻¹, resolution ≥4cm⁻¹
• Infrared microscope: magnification ≥320× (MCT low temperature detector required)
• ATR accessory: suitable for non-destructive testing of liquid samples

Core calculation parameters:

1. Aliphatic chain parameters (CH₂/CH₃): Reflects the degree of thermal evolution of organic matter
2. Aromatization index (1600cm⁻¹/1460cm⁻¹): Characterizes the aromatization process
3. Z factor (720cm⁻¹/750cm⁻¹): Distinguishes the source of parent materials

Typical application case: The maturity evaluation of Gulong shale in Daqing Oilfield shows that the CH₂/CH₃ ratio drops from 0.8 (low maturity) to 0.3 (high maturity)

Laboratory operation precautions:

• Strictly control humidity <60% to avoid the influence of KBr moisture absorption
• Background subtraction (blank wafer) is required before microscopic infrared analysis
• Regularly calibrate the instrument wavenumber accuracy with polystyrene standard sheets