Since Late Paleozoic

the four large-sized petroliferous basins (i.e.Ordos

Sichuan

Junggar and Tarim) in central-western China have experienced similar evolution processes during different geologic time

and have two kinds of petroleum exploration plays in clastic strata

i.e.self-source and self-reservoir type and marine-source continental-reservoir type.The clastic sequences deposited in compressional environments have "dual system tract structure"

which determines the high quality of the exploration plays.Three types(inner-sourcing

out-sourcing and hybrid-sourcing)and six subtypes of petroleum accumulation systems can be identified in the clastic sequences.The differences in tectonic deformation among these four basins result in the differences in their petroleum accumulation system distributions.A technique series consisting of 3D 3C seismic acquisition

processing and interpretation has been developed for fractured reservoir prediction.Seismic acquisition and processing techniques for loess tableland are developed to identify tight reservoirs and subtle traps.Fracturing techniques are developed for stimulation of the fractured tight reservoirs in western Sichuan depression.Compensation fracturing techniques are developed for stimulation of the tight sands in southern Ordos Basin.The advances in petroleum geologic theories and exploration techniques have promoted the discovery of the large- to medium-sized oil and gas fields (such as gas reservoirs in the 2

nd

member of Upper Triassic Xujiahe Formation

the classtic oil reservoirs in Tahe area

the Zhenjing oil field in southern Ordos Basin).