Evidence of fluid inclusion for thermal fluid-bearing hydrocarbon movements in Qiongdongnan Basin, South China Sea

Diagenetic research and inclusion observance indicate that there are seven types of inlcusion in the reservoirs in the Qiongdongnan Basin. Based on the fluorescence color, ratio of gas/liquid, formation temperature, salinity and organic component of fluid inclusions, three events of thermal fluid movement were found, and only the second and third events are relative to hydrocarbon migration and accumulation with the temperatures of 140–150°C and 170–190°C., respectively.The mechanism of gas migration in aqueous phase suggests that the discharging site of thermal fluid is the favourable location for natural gas accumulation. Project supported by the Natlonal Natural Science Foundation of China.