Controlling effect of tectonic-paleogeomorphology on deposition in the south of Lufeng sag, Pearl River Mouth Basin

Abstract

Paleogene depositional systems in the south of Lufeng sag have complex spatial distribution, which are influenced by pre-depositional paleogeomorphology and multiperiod tectonic activities. In this paper, to clarify the controlling effect of tectonicpaleogeomorphology 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.

Evaluation of petrophysical classification of strongly heterogeneous reservoirs based on the MRGC algorithm

“…Frontiers in Earth Science frontiersin.org Belt, the Southern Depression Belt, the Central Uplift Belt, the Northern Depression Belt, and the Northern Uplift Belt (Huizinga and Lomando, 1990;Leyla et al, 2018;Tian et al, 2020;Jiang et al, 2022;Shi et al, 2018). The Huizhou M oil field is located on the northwest slope of the Dongsha Uplift in the central uplift belt of the Pearl River Mouth Basin, south of the Huizhou depression, with reservoir depths of 2,284-2,620 m, which belongs to the middle depth.…”

Unreliable determination of in situ stress orientation by cross multipole array acoustic logging in fractured shale reservoirs

“…Unsealed secondary pores and fractures are suspected to be main factors controlling production. 40,43,44 The outcrop and FMI log data from the TX-1 well show that the strikes of fractures are NE-SW (40°-50°), with some striking N-S and NW-SE (Figure 4A); the dominant dip angle of the fractures is vertical (or subvertical) (Figure 3A,B), with some lowdip-angle tectonic fractures (Figure 4B).…”

“…Unsealed secondary pores and fractures are well developed in microfractures (Figure 3C); the pores in these fractures may be related to dissolution, and the secondary fractures may be related to late tectonic movement and multiple fracture openings. Unsealed secondary pores and fractures are suspected to be main factors controlling production 40,43,44 . The outcrop and FMI log data from the TX‐1 well show that the strikes of fractures are NE‒SW (40°–50°), with some striking N‒S and NW‒SE (Figure 4A); the dominant dip angle of the fractures is vertical (or subvertical) (Figure 3A,B), with some low‐dip‐angle tectonic fractures (Figure 4B).…”