The Characteristics Of Fluid Dynamics And The Effect On Hydrocarbon Accumulation In South Junggar Foreland Basin

Southern Junggar is foreland basin, at the effect of Himalayan tectonic movement, the pattern of hydrodynamic has significant changed. Overpressure is an important driving force for hydrocarbon migration. Utilization of a variety of techniques and method, make the research of distribution and evolution in major geological period. Explore the regularity of migration and accumulation.In this paper, on the base of field observation, the rock cores observing, logging date and related analysis of test data. Overpressure in the period of maximum depth was resumed using equivalent depth method, estimate the contribution of undercompaction in overpressure. Make use of the correlation between effective stress and speed of sound to estimate the contribution of the transmission in overpressure. Use the acoustic emission to test tectonic stress. Overpressure evolution history and hydrodynamic force distribution were obtained though basin numerical simulation. Contrast the new pattern of hydrocarbon as before, predict favorable reservoir area. Summary the feature of reservoir-forming rule at thrust belt and slopes in foreland basin.Research shows that undercompaction is ubiquitous in south Junggar foreland basin, it is the main reason of overpressure in slope zone. The undercompaction of Paleogene is Contributed about45%to overpressure in Sikeshu depression, about35%in the middle of Southern margin. Late Neogene has the maximum depth and most developed overpressure in Southern Junggar. The lateral overpressure difference between Horgos Anticline and Mosuowan salient is about26MPal, the vertical overpressure difference between Jurassic and Paleogene is about16MPa, it's the main accumulation period in Southern Junggar. Sedimentary hydrodynamic is the main driving force in Southern Junggar before Himalayan movement. It's distribution and evolution determines the hydrocarbons original accumulation area. Intense tectonic activity during Himalayan movement make hydrodynamic strong changed, fault communication different depth strata. Hydrocarbons migrated upward along the fault, make hydrocarbons loss along the fault or regrouped in the low fluid potential. Finally respectively forecast4favorable areas in Jurassic, Cretaceous and Paleogene.