Geology and reserve of the Orinoco heavy oil belt,Venezuela

Orinoco heavy oil belt is the largest heavy oil enriched area in the world,with the total area of 54 000 km2,heavy oil reserves of about 200 billion tons,and recoverable reserves of about 50 billion tons.It is located in the marginal uplift belt of East Venezuela Basin,and is a monocline dipping to the north.The main reservoir is Tertiary fluvial deltaic facies sandstone characterized by shallow depth of oil layer,large thickness,high porosity,high permeability,high oil saturation,poor consolidation,and strong heterogeneity.The main trap is lithologic trap,and locally controlled by faults.The belt is subdivided into 4 large areas with 32 blocks,and the proved reserves are mainly in the JUNIN and CARABOBO regions.Oil pools are characterized by "three highs and one low" in the fluidity of the heavy oil,that is,high gravity,high sulfur,high content of heavy metals vanadium and nickel,and low viscosity,and foamy oil can be formed.Under the conditions of cold production,the oil can flow and single well production is high,the production with horizontal well is up to 200 tons per day,and the oil recovery is relatively low(5%-10%).