Hydrocarbon Generation Kinetics of Lacustrine Yanchang Shale in Southeast Ordos Basin, North China

Abstract

The upper Triassic Yanchang shale in Southeast Ordos Basin (SOB) is a main potential source rock for conventional petroleum fields and has been recently recognized as an important unconventional reservoir. Here, we report on the hydrocarbon potential of this lacustrine shale using bulk and quantitative pyrolysis techniques. The rock samples were taken from the Chang7 and Chang9 intervals of upper Triassic-aged cores. The analytical program included total organic carbon (TOC), Rock-Eval, pyrolysis gas chromatography (Py–GC), source rock analyzer (SRA), and microscale sealed vessel (MSSV) pyrolysis. Phase kinetic modeling was also employed on the basis of these data sets. The results were used to determine the petroleum-type organofacies, bulk hydrocarbon composition during maturation, bulk and compositional kinetics, and phase behavior of fluids generated in the Yanchang shales. The shales proved to contain type II2 kerogen with organic matter in high abundance and generate paraffinic–naphthenic–aromatic (...