Status quo of tight oil exploitation in the United States and its implication

The exploration and development of shale gas in the U.S.is progressing fast,which also leads to the development of oil.Tight oil is the oil accumulating within the shale system,including black shale with very low permeability,argillaceous siltstone and interbeded sandstone.Tight oil can be free oil or absorbed oil.It is a continuous reservoir ofself-generation and self-storage.The development oftight oil in the U.S.mainlyperformed in Bakken,Eagle Ford,and the Barnett shale zone.Bakken shale has oil resource of 230×108 t and recoverable resource of 5.9×108 t.Bakken shale located within the U.S.has oil of 3.7×108 t and similar amount of associated gas.Its cumulative oil production since 2 000 is about 2.8×107 t.Eagle Ford shale produces oil in the northern part,annual oil production of about 2×105 t.Barnett shale has average undiscovered oil resource of 1.4×107 t,ofwhich undiscovered oil resource is 4.8×106 t.At present,Barnett shale has more than 8 000 producing wells,mainly produces oil in the northern part,gas in southern part.Up to the end of 2009,the cumulative oil production of tight oil zone has reached 7.7×106 t.China is a countryrich in black shale.It is expected that the exploration oftight oil will get breakthrough soon.