The shelf margin delta of the Zhuhai Formation in the southern subsag of the Baiyun sag in the Pearl River Mouth Basin is a focus for domestic deep-water research and an important deep-water exploration target. Based on the surrounding drilled wells, thin section and physical property analysis data, the characteristics of the reservoirs in Zhuhai Formation are investigated, the main factors affecting physical properties are discussed and favorable reservoir distribution is predicted. The result shows that reservoirs with good physical properties had developed in all the delta intervals of the Zhuhai Formation, and the physical properties of the reservoirs decrease with an increase of burial depth. The 1st and 2nd Members of the Zhuhai Formation have the best physical properties. These are mainly medium-high porosity and medium-high permeability. The 3rd and 4th Members of the Zhuhai Formation have medium-high porosity, extra low permeability-high permeability. The 5th and 6th Members of Zhuhai Formation are relatively poor, and have mainly low porosity and low permeability-extra low permeability. The reservoirs on the shelf margin delta of the Zhuhai Formation are controlled by sedimentary facies belts, compaction, and basin heat flow background. Sedimentary facies belts provide the material basis of the reservoirs, and high-quality reservoirs are developed in the high-energy facies belts of the delta front. The compaction was only strong before the 4th Member of the Zhuhai Formation, and the compaction was not strong during the main development period of the shelf margin delta. The high geothermal gradient in the southern subsag of the Baiyun sag promotes the acceleration of diagenesis and the deterioration of the physical properties of the reservoir, but it also has led to secondary pore development zones. The threshold of the burial depth of the reservoir physical properties is 2400~2600 m, indicating that the physical properties of the 4th Member and above of the Zhuhai Formation are relatively good. Favorable reservoirs in the Zhuhai Formation are characterized by high thermal sag, shallow burial and superior facies. They are mainly high-energy facies belts at the front of the shelf margin deltas and deep-water fans near the delta, the physical properties of deep-water fans relatively far from the delta have deteriorated. The shelf margin delta front and deep water fans from the 3rd Member to the 1st Member of the Zhuhai Formation form favorable reservoirs. The most favorable reservoirs developed in the 1st Member of Zhuhai Formation because of its large scale and best physical properties and they can be key exploration targets. The 5th and 6th Members of the Zhuhai Formation are mainly important reservoirs when superior facies and secondary pore development zones exist.

Paleogene depositional systems in the south of Lufeng sag have complex spatial distribution, which are influenced by pre-depositional paleogeomorphology and multi-period tectonic activities. In this paper, to clarify the controlling effect of tectonic-paleogeomorphology on sedimentary facies distribution and effectively guide oil and gas exploration, the Paleogene paleogeomorphic pattern in the south of Lufeng sag is reconstructed by the impression method, and the temporal and spatial evolution laws of the main faults are clarified. The results show that braided river deltas developed stably in the long-axis gentle slope belt of the lake basin, while the short-axis sedimentary system changed from fan deltas to braided river deltas in response to the change of active strength of dominant faults from strong to weak. It is found that the scale of the sedimentary fan is closely related to the activity of the main fault, the area of the catchment, and the vertical elevation difference. The steep cliff is controlled by the boundary fault with large fault throw and steep section, and there are wedge-shaped sand bodies near the steep cliff. The multi-level fault-step zone provides the driving force for the advancement of the sedimentary system, and the sand body extends for a long distance. It is established that the supply capacity of the source area and the accommodated space of the lake basin are coupled to control the deposition scale. Moreover, the slope controlled by the combination of paleogeomorphic assemblage and the activity of the main fault determines the sedimentary type, and the structural slope-break zone defines the spreading pattern of the sands.