Coarse-grained clastic fan subtle traps are well developed in the Hassan block of Junggar Basin.However

the coarse-grained clastic deposits are commonly complexes composed of multiple coarse-grained clastic fans deposited at different geological times.As their internal structures are very complicated

the identification of subtle traps is difficult.Taking the coarse-grained clastic fan of the lower Badaowan Formation of the Jurassic in Hassan block as an example

we identified sequence boundaries and analyzed features of sedimentary cycles in single well by using the sequence stratigraphy method

then performed fine division of the deposits stages of coarse-grained clastics

and finally established a stratigraphic framework.Furthermore

sedimentary section

logging and test data

and regional sedimentary facies were integrated to carry out stratigraphic correlation and layer subdivision and select target sandbodies.By using various geophysical techniques such as seismic attribute extraction and seismic facies

we accurately identified the subtle traps in the Hassan block.Commercial oil flow was tested in these subtle traps

marking a big breakthrough of exploration in this block.These methods may be also effective for identification of subtle traps in similar blocks.