
Petroleum Biomarker Interpretation for Geochemical Analysis
Interpret petroleum biomarkers to assess source rock maturity and depositional environment
What You Can Do
You can interpret complex biomarker data from crude oils and sediments—including steranes, hopanes, and aromatic compounds—to reconstruct petroleum systems and make exploration-relevant conclusions. This skill helps you assess thermal history, identify source rock depositional environments (marine vs. terrigenous, anoxic vs. oxic), correlate oils to sources in multi-source basins, and validate thermal maturity when vitrinite reflectance data is limited. Your interpretations directly support drilling decisions, reserve estimations, and field development strategies.
Features
assess thermal maturity, source rock organic matter type, and biodegradation history
evaluate source rock depositional environment and diagenetic alteration patterns
use biomarker parameters as secondary maturity indicators when vitrinite reflectance is unavailable
match oils to potential source rocks in frontier and multi-source basins
track hydrocarbon movement through trap configurations using biomarker signatures
distinguish anoxic/oxic depositional settings and terrigenous vs. marine organic matter input
validate Rock-Eval and vitrinite reflectance data against biomarker maturity parameters
structure chromatographic observations into defensible geochemical conclusions
Example Output
Example 1: Source Rock Characterization
Input: Biomarker chromatogram showing high pristane/phytane ratio (>3.0), elevated C29 steranes (>40% of total steranes), and low aromatic steroid/sterane ratio.
Output: ✓ Predominantly Type II kerogen from marine shelf depositional environment ✓ Oxic to suboxic paleoenvironment with terrestrial organic matter influence ✓ Maturity assessment: Early-to-mid oil generation window (Ro ~0.6–0.8%) ✓ Risk flag: Immature intervals present; verify with vitrinite reflectance
Example 2: Oil-to-Source Correlation
Input: Crude oil biomarker profile (C27/C28/C29 sterane ratios, hopane/sterane ratio, Ts/Tm) compared to three potential source rock extracts.
Output: ✓ Strong correlation with Source Rock B: identical sterane carbon number distribution (C27 35%, C28 28%, C29 37%) ✓ Matching hopane maturity patterns and aromatic steroid profiles ✓ Alternative sources ruled out: different depositional environments evident from pristane/phytane ratios ✓ Conclusion: Oil A likely migrated from Source Rock B via seismic-defined migration pathway
Example 3: Thermal Maturity Validation
Input: Vitrinite reflectance Ro = 0.55%, but biomarker maturity parameters (Ts/Tm, %MPI, aromatic steroid isomerization) suggest higher maturity (Ro ~0.75%).
Output: ✓ Discrepancy flagged for quality control review ✓ Potential causes: reworked vitrinite, poor sample preparation, or biomarker signal from mature source ✓ Recommendation: Repeat vitrinite analysis; conduct kinetic modeling using biomarker-derived maturity as constraint
What's Included
- SKILL.md instruction file: complete petroleum biomarker interpretation framework with principles and systematic workflow
- Biomarker ratio reference matrix: quick-lookup table for sterane, hopane, and aromatic compound interpretations
- Interpretation decision tree: flowchart guiding thermal maturity, source character, and environment assessment
- Oil-to-source correlation template: structured worksheet for multi-sample biomarker correlation studies
- Risk assessment checklist: maturity validation, data quality, and exploration decision support flags
Who It's For
- Exploration geochemists — assess petroleum systems and reduce drilling risk in frontier basins
- Reservoir development geochemists — correlate oils to sources and optimize field development strategies
- Geochemical consultants — validate thermal maturity data and provide source-to-oil interpretations for oil and gas companies
- Basin modeling specialists — use biomarker maturity and source characterization as kinetic model inputs and constraints
- Operations teams — support drilling decisions with rapid biomarker-based source and maturity assessments
Best For
- Thermal maturity assessment when vitrinite reflectance data is limited or unavailable
- Crude oil-to-source rock correlation in multi-source petroleum systems
- Paleoenvironment and depositional setting interpretation from biomarker signatures
- Quality assurance validation of Rock-Eval and reflectance analytical data
- Exploration risk assessment and drilling decision support presentations







