COMPARATIVE ROCK-EVAL PYROLYSIS AS AN IMPROVED TOOL FOR SEDIMENTARY ORGANIC-MATTER ANALYSIS

An improved Rock-Eval pyrolysis method is described for the global and exhaustive characterization of kerogen and bitumen in rock samples. Comparative pyrolysis is derived from the original Rock-Eval method of Espitalie et al., it overcomes some of its inadequacies and allows a better exploitation of the pyrolysis data. This new pyrolysis method is proposed mainly for routine analysis of bitumen in rock samples, using a double analysis of each sample (on whole rock and extracted rock). The difference between these two pyrolysis curves corresponds to the bitumen pyrolysis curve and is used for estimating the total bitumen content. The bitumen yield obtained in comparative pryolysis as a good correlation with the bitumen yield obtained by the standard solvent extraction method with, however, some limitations due to the "mineral matrix effect". The bitumen pyrolysis curve is further subdivided into three fractions, which allow a quick and easy typing of bitumen products. This method has been successfully applied to basin analysis.