关键词: 生烃动力学, 烃源岩, 南二凹, 南黄海盆地

Abstract: Hydrocarbon resource potential in the South Yellow Sea Basin has always been a concern for offshore exploration in China, but no breakthrough has been made yet. The kinetics of hydrocarbon generation is very important for the evaluation of hydrocarbon generation potential of source rocks, and the researches of hydrocarbon generation kinetics of Paleogene shale is very weak in the study area. Hence, based on the conventional geochemical analysis and statistics of source rocks in the Southern Depression, South Yellow Sea Basin, low-mature samples in the Naner Sag were selected for experimental analysis such as PY-GC, SRA, MSSV, and then they were used for kinetic simulations. The results demonstrated that the fourth members of Funing Formation in Naner Sag has entered the early stage of hydrocarbon generation, and its predicted petroleum type was paraffinic-naphthenic-aromatic (PNA) low wax oils. The distribution range of the activation energy is 43-60 kcal/mol, with the main peak at 51kcal/mol accounting for 72% of the total. The frequency factor of the bulk petroleum generation is A=9.66×1012 and the temperature of the hydrocarbon generation window ranges from 128 to 158℃. The hydrocarbon generated from the whole evolution process existed as two-phase fluid in the Funing Formation at the end of Oligocene (23-30 Ma), and in the rest of the time period as a single liquid phase. And the conversion rate (TR) of these source rocks was still between 50% and 60%. The hydrocarbon generation kinetics of the Paleogene shale of Naner Sag in South Yellow Sea Basin obtained in the study is very important for the estimation of hydrocarbon resource potential and provides theory basis for the further petroleum exploration and exploitation decision in this region.

Key words: kinetics of hydrocarbon generation, source rock, Naner Sag, South Yellow Sea Basin