Dominant Migration Pathway and Its Control on Oil-Gas Migration in the Northern Edge of Qaidam Basin

Dominant migration pathway is an effective method for predicting hydrocarbon migration and favorable traps. Dominant migration pathway can be mainly divided into four models including predominances caused respectively by porosity and permeability difference relative to surrounding rocks, excursion of sedimentation center of caprocks, fluid pressure, or fault obliquity. Based on studies on sandbody distribution, paleo-fluid potential in pool-forming period, fault obliquity and excursion of sedimentation center of caprocks, the distribution and controlling on hydrocarbon migration of every types of dominant migration pathways in the northern edge of Qaidam basin were expatiated. And then hydrocarbon migration and favorable traps in the northern edge of Qaidam basin were predicted by integrated the controlling on hydrocarbon of different types of dominant pathways. The study results show that Lenghu-Nanbaxian structural belt is the most favorable accumulation zone for it is located in the area of four types dominant pathways, followed by Eboliang-Hulushan structural belt, and structural heights of No.7 Lenghu structure and Hulushan structure are the most favorable exploration targets.