Dynamics Of Hydrocarbon Accumulation Of The EBoLiang Structural Belt In The West Section Of The Northern Margin Of Qaidam Basin

Tertiary and Jurassic system in the west of North Qaidam Basin are rich in oil and gas resourse, Jurassic coal measure strata as the main oil and gas system for source rock. The distribution of reservoir hydrodynamic force influences the law of gas migration and accumulation, consequently, through this paper research will have certain guiding significance for geological exploration and development.In the process of research, overpressure at the deepest burial depth is restored by equivalent-depth method, it analyses undercompaction leads to hydrodynamic force distribution at the deepest burial depth. It qualitatively analyses hydrocarbon generation contributes to abnormal pressure, which is used by correlation between measured overpressure data and generation potential of hydrocarbon. The relationship between abnormal pressure and temperature qualitatively analyses aquathermal pressure boost contributing to abnormal pressure. The relationship between effective stress and sound velocity quantitatively analyses overpressure transference contributing to overpressure in order to analyze formation mechanism of abnormal pressure. Hydrodynamic force distribution in every stages and evolution characteristics are restored by numerical simulation, discussing the effects of which to oil-gas migration and accumulation. The dominant carriers of gas migration are divided by the correlation between differential overpressure with source and reservoir and gas potential energy gradient.Study shows that abnormal high pressure in Eboliang region mainly derives from undercompaction, overpressure transference and tectonic compression. Undercompaction makes contribution the most, of which Paleogene accounting for41%.Overpressure transference accounts for53%. Hydrocarbon generation and aquathermal pressure boost makes less contribution to abnormal pressure. Fluid potential energy distribution in Eboliang region totally presents the trend of high southwest and low northeast. Based on gas potential energy study, hydrocarbon migration and accumulation system are different in different layer and stage. Finally in the direction of differential overpressure with source and reservoir and decreasing potential gradient, it confirms the upper Ganchaigou Formation that At different times the dominant carriers of oil-gas migration and accumulation are Eboliang II structure, Eboliang Ⅲstructure, No.6Lenghu structure,No,7Lenghu structure, HulouShan structure and YikeYaWuRu region.