Abstract:

Based on the recent oil and gas exploration data of Baodao northern slope in the Qiongdongnan Basin and the analyses of
target reservoir rocks of the Baodao northern slope, the oil-gas-bearing possibility was evaluated by quantitative grain fluorescence
experiments. In combination with oil-gas charging time, stages of fault activity and some other geological background, oil-gas
distribution characteristics of Baodao northern slope were analyzed. The results show that the target reservoir, i.e., the Sanya Formation,
belongs to mid porosity and low permeability reservoir. Also, the pores are mainly intergranular and biological visceral pores, and the
reservoir shows strong heterogeneity with high mud content. The oil and gas reservoirs of the Sanya Formation of Baodao northern slope
formed very late. So the particle surface adsorbed hydrocarbon abundance of shallow Sanya Formation is prevalent high with low
abundance of intragranular hydrocarbon. However, the oil and gas reservoirs of the Lingshui Formation, close to the Baodao sag, formed
much earlier, but most of them were destroyed later. Therefore the particles of reservoirs have high abundance of intragranular
hydrocarbon with low adsorbed hydrocarbon abundance. Because of the limited migration ability, the oil and gas generated from the
Baodao Sag is mainly influenced the B area of Baodao northern slope and they have little contribution to the A area of Baodao northern
slope, which is located at the northern part of the Songtao bulge. Through the widely developed faults, the oil and gas generated by the

Oligocene source rock migrated vertically and accumulated in the reservoir of the Sanya Formation very late. And the characteristics of
the oil and gas are different from those of the oil and gas from other areas

Key words: quantitative grain fluorescence, oil-gas-bearing possibility, reservoir rock, accumulation model, Baodao northern slope;
Qiongdongnan Basin