in: Advances in Petroleum Source Rock Characterizations: Integrated Methods and Case Studies, Haytham El Atfy and Bandar I. Ghassal, Editor, Springhouse Corporation , Zürich, pp.47-57, 2023
Open system pyrolysis (e.g., Rock–Eval) is widely used
screening technique for hydrocarbon source rock characterization. It is preferred because it is rapid, practical and
cost-effective. However, some pitfalls exist due mainly to
sample conditions and care must be exercised. One of the
major problems occurs when source rock samples are
contaminated by organic additives from the drilling fluids.
Analyses of contaminated samples inevitably result in
misrepresentative conclusions, possibly leading to incorrect directions. This paper revisits some previously
reported problems due to contamination and discusses
available remedies. Decontaminating source rock samples
is conventionally accomplished by solvent extraction.
However, a recent method called thermo-vaporization is
equally successful in decontaminating samples prior to
pyrolysis. In the case of concern about determining the
true thermal maturity of samples contaminated with
persistent contaminants, we remind the reader and discuss
a recently proposed method, namely Oxidation Tmax.
Finally, although pyrolysis is a rapid screening technique,
sole dependence upon pyrolysis for petroleum source
rock characterization must be avoided. At the least, for
some selected samples, assessments should be based on
integrated organic geochemical and organic petrographic