关键词: 地震属性, 砂砾岩, 地层对比, 隐蔽油气藏, 八道湾组, 准噶尔盆地

Abstract:

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.

Key words: seismic attribute, coarse-grained clastics, stratigraphic correlation, subtle trap, Badaowan Formation, Junggar Basin