To discuss the prospecting potential of shale oil in the 3

rd

sub-member of the Triassic Chang 7 member(Chang 7

3

) in Binchang block

southwestern Ordos Basin

the oil content and oil occurrence of typical rock types in Well B-1 were systematically observed and evaluated based on systematic observation and description of cores and using the results of Rock-Eval pyrolysis

thermovaporization in different temperature ranges and organic petrological analysis in combination with scanned images of cores with white light and fluorescence.The results show that the cored interval in Chang 7

3

from Well B-1 is quality source rock at early stage of major oil window.The black laminated shale and layered mudstone are characterized by high oil content but dominance of immobile oil

and the average OSI is 45 mg/g(n=116)

indicating no prospecting potential for shale oil.Whereas

the gray-brown laminated

thin-bedded and massive tuff and the interbedded tuffaceous(argillaceous) siltstone are characterized by high oil content

predominance of free oil and contributions from migrated oil.The oil mainly occurs in microfractures

intergranular pores and grain boundary fractures of detrital minerals

and its average OSI is 200 mg/g(n=28)

indicating good prospecting potential for shale oil.In conclusion

the gray-brown tuff and the interbedded tuffaceous(argillaceous) siltstone on the Yishan slope in Binchang block are favorable intervals for shale oil exploration and have some shale oil prospecting potential.