Abstract
Geological analysis and physical analogy experiments indicate that, under geological conditions, hydrocarbon tends to migrate along a path of least resistance and attempt to follow the largest buoyancy component. There are four generalized modes of possible transport. First, hydrocarbons tends to migrate along the pathways with high porosity and permeability, and with a large grade difference relative to surrounding rocks (grade difference predominance); second, hydrocarbons tends to migrate in the opposite direction in overlying formations to the nadir of the sedimentation centre (divided syncline predominance); third, hydrocarbons tends to migrate in the direction of lower fluid pressure (fluid pressure predominance); fourth, hydrocarbons tends to migrate in the direction vertical to buoyancy (flow direction predominance). This paper reports on field observations in the Daqing oilfield area of China and also on physical analog experiments used to illuminate the four basic modes of transport. Under geological conditions, the hydrocarbon migration pathways are controlled by these four basic modes, which can be used to predict the directions of hydrocarbons migration and select favourable exploration locations.