Analysis on migration path and convergence ability of Neogene target traps in steep belt of rifted basin: A case study of the eastern steep slope of the Miaoxibei Uplift in Bohai Sea

Abstract

Objective The size of Neogene reservoir formation in rifted basins is closely linked to deep oil and gas accumulation and three-dimensional transport systems. Methods This study examines the differential oil and gas charging issues associated with target traps in Neogene fault basins. Using the eastern steep slope of the Miaoxibei Uplift in the Bohai Sea as an example, we analyze the components of the oil and gas accumulation system in steep slope zones by evaluating fault conduction capability and dividing the dominant injection segments. Subsequently, oil and gas migration simulations are conducted under the control of the fault injection section. Results The research findings are as follows: ① The accumulation system in the steep slope zone consists of deep hydrocarbon accumulative sand bodies, large boundary faults, and late shallow faults. ② The dominant hydrocarbon sinks in the three parts of the accumulation system interact with each other, forming a dominant migration path that is reflected in the overlapping fault charging section with the target trap. The middle section of the main migration fault on the east side of the Miaoxibei Uplift is a strong charging area, while the northern section is a medium charging area. Among the secondary migration faults, faults 4, 6, and 8 have developed strong charging sections, while faults 1, 2, and 11 have developed medium charging sections. ③ Structural migration simulations reveal that the oil and gas accumulation area develops in the middle of the steep slope zone in the east of the Miaoxibei Uplift, with two main migration routes in the east and one in the south. The typical sand traps in fault No. 3 have developed four accumulation zones, with accumulation zone C being the most significant. Conclusion In conclusion, these research findings can serve as a reference for well deployment in target areas, and the technical methods employed can provide support for hydrocarbon accumulation analysis.

Keywords

• accumulation system
• migration path
• charging section
• transport simulation
• the eastern of miaoxibei uplift
• steep belt
• rifted basin