Quantitative description of transfer capability of transporting ridges and its implication in hydrocarbon exploration in eastern area of Bohai Sea

Key words:  Neogene in eastern area of Bohai Sea  unconformity of buried hill  body sand  transfer capacity of transporting ridge  quantitative description

Abstract:

Based on the study of hydrocarbon migration conditions in the eastern area of Bohai Sea, models of lateral accumulation and vertical transfer of transporting ridges for buried hill unconformity and body sands in the bottom of the Guantao formation were established, and further quantified the transfer capacities for shallow Neogene accumulation. The results show that the accumulation capacity of buried hill unconformity is related to contact size between source rock and ridge, ridge dip and trap area on the ridge. An index of accumulation (I_a) for transporting ridge is introduced which combines known oilfields data. A ten-million-tons class Neogene oilfield above the buried hill can be predicted if I_a is bigger than 30 km·km². Transfer capacity of sand body ridge in the Guantao formation is controlled by the trap area on the ridge, ridge dip, configuration between ridge and fault, and fault activity. A non-dimensional index of difference (I_d) and an index of transfer (I_t) are established from successful reservoirs to show that the transfer capacity of sand ridge becomes beneficial for shallower accumulation if I_d is smaller than 0.5 and I_t is larger than 100. The study provides insights into quantitative description of transporting ridge' transfer capacity, and has proven a successful implication in the Neogene exploration of slope zones in the eastern area of Bohai Sea.