Fluid inclusion evidence for a coupling response between hydrocarbon charging and structural movements in Yitong Basin, Northeast China

Abstract

For this study 145 fluid inclusion samples from 19 wells have been analysed to unravel the relationship between the complex charging history and tectonic evolution of the Yitong Basin, Northeast China. Fluid inclusion petrography, microthermometry, transmitted light microscopy and micro fluorescence observation methods were employed to systematically obtain information on fluorescent colors of hydrocarbon inclusions, homogenization temperatures of oil inclusions and their coeval aqueous inclusions. The results indicate three events of oil charging and one gas charging event for the Paleogene reservoirs. The oil charging events have been reconstructed at 38.1–27 Ma, 19.5–10 Ma and 1–0 Ma, while the gas charging event most likely occurred at 1–0 Ma. When combining the known information on hydrocarbon charging history and structural evolution, two intermittent periods of hydrocarbon migration and accumulation are likely to have occurred at 27–19.6 Ma and 10–2 Ma, coupling to two structural events. It is suggested that these events caused the termination of hydrocarbon supply or destruction of the previously accumulated hydrocarbons.