Abstract: Analysis of steride terpane maturity and oil production test data revea1s, on the one hand, the petroleum resources generated in Biyang sag, and on the other hand,shows that not only low mature commercial oil flow but also mature oil (gas) flow were found in the center of the sag and that high mature petroleum resources also can be found in the lower He III and deep series strata. The following are concluded: dolomite reservoirs in the center of the sag are the most realistic exploration area atpresent, new exploration area in Biyang sag is the'depressed zone, targets are deep series strata with thelower He III being the focus, key task is searching forsand bodies, and reservoirs are mainly non -structuralreservoirs.