Because sedimentary organic matter consists of a diverse mixture of organic components with
different properties, a combination of chemical and petrographic results offers the most complete
assessment of source rock properties. The primary purpose of this Society for Organic Petrology (TSOP)
subcommittee is to contribute to the standardization of kerogen characterization methods. Specific
objectives include: (1) evaluation of the applications of different organic matter (petrographic) classifications
and terminology, and (2) integration of petrographic and geochemical results. These objectives
were met by completing questionnaires, and petrographic, geochemical and photomicrograph round-robin
exercises. Samples that were selected for this study represent different petrographic and geochemical
properties, and geologic settings to help identify issues related to the utilization of different classifications
and techniques. Petrographic analysis of the organic matter was completed using both a prescribed
classification and the individual classification normally used by each participant. Total organic carbon
(TOC), Rock-Eval pyrolysis and elemental analysis were also completed for each sample. Significant
differences exist in the petrographic results from both the prescribed and individual classifications.
Although there is general agreement about the oil- vs gas-prone nature of the samples, comparison of
results from individual classifications is difficult due to the variety of nomenclature and methods used to
describe an organic matter assemblage. Results from the photomicrograph exercise document that
different terminology is being used to describe the same component. Although variation in TOC and
Rock-Eval data exists, geochemical results define kerogen type and generative potential. Recommendations
from this study include:
(1) A uniform organic matter classification must be employed, which eliminates complex terminology
and is capable of direct correlation with geochemical parameters.
(2) A standardized definition and nomenclature must be used for the unstructured (amorphous)
organic matter category. Subdivisions of this generalized amorphous category are needed to
define its chemical and environmental properties.
(3) Standardized techniques including multimode illumination, types of sample preparations and
data reporting will help eliminate variability in the type and amount of organic components
reported
