Eight different samples of various locations have been analysed during the practical course. The
samples consisted of two source rock samples (Kimmeridge Clay and Blue Lias), two oil sands
(Wealden oil sand and Osmington Mills oil sand) and four oil samples including Libya oil, R828, Iraq
oil (09_205) and Schwedeneck. The Kimmeridge Clay represents an immature source rock with very
good potential. The Blue Lias source rock, kerogen type II, shows the same conditions as the
Kimmeridge Clay. The other Kimmeridge Clay sample kimsrf 1 indicates kerogen type I. The Wealden
oil sand shows intense biodegradation and plots in the area of a type II kerogen. The Osmington Mills
oil sand plots in type I kerogen area, and also shows intense biodegradation. The Libya oil is
comprised of a type II/III kerogen, similar to the R828 oil sample which additionally shows oxidizing
marine conditions. Iraq oil plots in the area of a type II kerogen and was deposited under marine
hypersaline conditions. The last sample, the Schwedeneck oil, was deposited under rather oxidizing
conditions and sterane analysis suggests an early oil window stage.
Table of Contents
I. Summary
II. Introduction
III. Results and Discussion
i. TOC
ii. Rock Eval
iii. Bitumen Extraction
iv. Asphaltene Precipitation
v. IATROSCAN (TLC-FID analysis)
vi. GC
vii. GC-MS
IV. Conclusion
V. References
VI. Experimental Procedures
Objectives and Topics
The primary objective of this laboratory course was to evaluate the kerogen type, depositional environment, thermal maturity, and petroleum potential of selected source rock and oil sand samples collected from South England. By employing industry-standard geochemical screening and characterization methods, the study aims to quantify biomarker compositions and assess the preservation of organic matter across different geological origins.
- Application of TOC measurements and Rock-Eval Pyrolysis for bulk source rock characterization.
- Chromatographic separation and semi-quantitative analysis of bitumen fractions (saturated, aromatic, NSO).
- Identification and quantification of biomarker compounds using Gas Chromatography (GC) and Gas Chromatography-Mass Spectrometry (GC-MS).
- Determination of depositional environments and maturity levels using specific geochemical ratios and diagrams.
Excerpt from the Book
II. Introduction
The aim of the laboratory course „Petroleum Geochemistry“ in the winter term 2013/2014 was to assess the kerogen type, depositional environment, maturity and petroleum potential of source rock and oil sand samples, using standard geochemical screening and characterization methods. The experimental procedures were based on the Norwegian Industry Guide to Organic Geochemical Analyses (NIGOGA). They comprise screening methods on bulk source rocks such as TOC measurements and Rock-Eval Pyrolysis, as well as semi-quantitative analysis of bitumen composition by means of chromatographic separation. The fractions gained by liquid column chromatography (saturated, aromatic, NSO) were further characterized by GC and GC-MS measurements, allowing the recognition and quantification of biomarker compounds. The schematic work flow according to the NIGOGA guide is depicted in figure 1 (Appendix).
The set of samples (see Table 1) comprises two Source Rocks and two Oil Sands, all collected during the field trip “Reservoir Petrology” in South England in September 2013. The exact locations where the samples were found are shown in figure 2 (Appendix). For the GC and GC-MS analysis some of the samples were substituted by those from the year before because in those the biomarkers were better preserved. In addition, three oils from different locations were examined. Again, for the GC MS analysis an additional Oil from Schwedeneck was analyzed because it was suitable for exhaustive biomarker analysis.
Chapter Summary
I. Summary: Provides an overview of the eight samples analyzed, identifying their kerogen types and depositional conditions, ranging from immature source rocks to biodegraded oil sands.
II. Introduction: Outlines the laboratory course's goal of assessing petroleum potential through standard geochemical methods like TOC, Rock-Eval, GC, and GC-MS, following the NIGOGA guide.
III. Results and Discussion: Presents the findings from various analytical methods, including TOC contents, Rock-Eval pyrolysis, bitumen extraction, asphaltene precipitation, IATROSCAN analysis, and detailed biomarker interpretation via GC and GC-MS.
IV. Conclusion: Summarizes the final interpretations for each sample, confirming depositional environments, kerogen types, and maturity levels based on the conducted geochemical analysis.
V. References: Lists the essential industry manuals and academic literature, specifically the NIGOGA guide and the biomarker guide by Peters et al., that provided the scientific framework for the report.
VI. Experimental Procedures: Details the specific laboratory protocols used for each analytical method, ensuring transparency regarding how samples were processed, heated, and measured during the experiments.
Keywords
Petroleum Geochemistry, Source Rock, Oil Sand, Kerogen Type, TOC, Rock-Eval Pyrolysis, Bitumen Extraction, Asphaltene, IATROSCAN, Gas Chromatography, GC-MS, Biomarkers, Maturity, Depositional Environment, NIGOGA
Frequently Asked Questions
What is the core focus of this laboratory report?
The report focuses on the geochemical characterization of various source rock and oil sand samples collected in South England to assess their petroleum potential and origin.
What are the central thematic fields covered in the document?
The document covers organic geochemistry, specifically bulk screening methods (TOC, Rock-Eval), chromatographic separation, and molecular-level biomarker analysis using GC and GC-MS.
What is the primary research goal?
The primary goal is to determine the kerogen type, maturity level, and depositional environment of the samples to understand their viability as petroleum sources.
Which scientific methods are primarily employed?
The study utilizes standard methods including TOC/TIC measurement, Rock-Eval Pyrolysis, IATROSCAN (TLC-FID), Gas Chromatography, and Gas Chromatography-Mass Spectrometry (GC-MS).
What is covered in the main section of the document?
The main section details the analytical results of specific samples (e.g., Kimmeridge Clay, Blue Lias, various oil sands) and interprets them using established geochemical ratios and plotting techniques.
Which keywords define this work best?
Key terms include Petroleum Geochemistry, Kerogen, Biomarkers, Rock-Eval, GC-MS, and maturity indicators.
Why was the Kimmeridge Clay sample analyzed multiple times?
The sample was analyzed in duplicates to ensure the reliability of the high TOC results obtained and to compare potential variations in the measurements.
What role does the NIGOGA guide play in this study?
The Norwegian Industry Guide to Organic Geochemical Analyses (NIGOGA) serves as the standard operational protocol for all experimental procedures described in the report.
What conclusion does the author draw regarding the Blue Lias source rock?
The author concludes that the Blue Lias is a type II, marine kerogen with very good potential, though some maturity parameters (specifically Ts/Ts+Tm) suggested potential contamination or environmental influence.
How does the IATROSCAN method contribute to the analysis?
IATROSCAN (TLC-FID) is used to categorize the relative composition of the oils into saturated hydrocarbons, aromatic hydrocarbons, and NSO/asphaltene components to distinguish between normal crude oils and degraded samples.
- Quote paper
- Amalia Aventurin (Author), 2014, Petroleum Geochemistry, Munich, GRIN Verlag, https://www.grin.com/document/278498
