Qu, X.-Y.; Chen, S.-R.; Yang, X.-B.; You, L., and Zhong, J., 2019. Study on hydrocarbon accumulation period in deep water areas of the South China Sea: An example from the Miocene reservoir of the Ledong-Lingshui Sag in the Qiongdongnan Basin. In: Gong, D.; Zhu, H., and Liu, R. (eds.), Selected Topics in Coastal Research: Engineering, Industry, Economy, and Sustainable Development. Journal of Coastal Research, Special Issue No. 94, pp. 112–116. Coconut Creek (Florida), ISSN 0749-0208.

According to the observation of fluid inclusions under microscope and the measurement of homogenization temperature, this paper studies the accumulation period and the characteristics of fluid inclusions of the miocene reservoir of Ledong-lingshui sag in Qiongdongnan basin. The results show that the fluid inclusions are mainly distributed along the quartz fracture zone while some are at the edge of the quartz grains or cut through several clastic grains. The fluid inclusions mainly include brine inclusions, liquid hydrocarbon inclusions, hydrocarbon inclusions and liquid hydrocarbon inclusions, in which hydrocarbon inclusion is at the third stage of development, which are mostly yellow blue and white when exposed to fluorescent light. The maturity of organic matters is relatively high. The homogenization temperature of fluid inclusions is discontinuously distributed, the peak values of which are mainly concentrated in the range of 130 -150°C. According to the characteristics, occurrence and homogenization temperature of the fluid inclusions, Miocene reservoirs are mainly composed of three-phrase hydrocarbon fluid filling and first-stage CO₂ fluid filling. Among them, the second and third-stage hydrocarbon fluid filling is the main hydrocarbon generation stage, and the CO₂ fluid filling occurs in the late stage of gas charging. Considering the burial history and thermal evolution history, the accumulation period belongs to 1.9Ma-1Ma, which is the late Pliocene of Neogene of Yinggehai- Pleistocene of Quaternary of Ledong.