Some Predicted Effects of Minerals on the Generation of Petroleum in Nature

Abstract

The presence of some minerals can strongly influence the composition of laboratory pyrolysates. The question is whether similar effects may also occur in nature, thereby influencing the gas–oil ratio and other bulk compositional characteristics. A series of experiments have been conducted at varying heating rates to examine this issue. Three source rocks that vary significantly in mineralogy (a quartz-rich, a calcite-rich, and a clay-rich sample), namely, the Alum shale, Bowland shale, and Toolebuc oil shale, respectively, were tested by Rock-Eval pyrolysis, open-system pyrolysis gas chromatography (PyGC). and bulk kinetic parameters to check for the existence or otherwise of mineral matrix effects (MMEs). Kerogen and whole-rock samples were then pyrolyzed at three heating rates using closed-system [microscale sealed vessel (MSSV)] pyrolysis to examine the heating rate dependency upon hydrocarbon aromaticity, gas–oil ratio, and total yield. The solvent extract of one Bowland shale sample was used as a ref...