Abstract: In Dongpu sag and subOdepressions , favarate exploration target may exist in source rocks while in the Central uplift it may exist under the cap rock. There is no fault in the subOdepressions and the beds are successive , where hydrocarbon migrates laterally and may accumulate when favorable traps are encountered. If there are some faults , it may migrate upward to high part then accumulate at the places with good trapping , migrating and preserving conditions. Take Baimiao structural reservoir as example , it is mainly supplied by Qianliyuan subO depression ( the largest oilOgenerating subOdepression in this area) , the 1source rock is Qianliyuan S33～4interval , hydrocarbon may accumulate primarilyin Qian block 8 adjacent to oilO generating ubO epression , then migrate to high position of Baimiao structure along ault . For this migrating and reservoir forming action , the reservoir distribution pattern in Baimiao is formed: middle and shallow accumulation is dominant at the high part while middle and deep accumulation is dominant at he low.

Key words: Dongpu sag, oil and gas reservoir, structure