MATURITY STUDY OF THE STRONG BIODEGRADATION VISCOUS OIL：TAKING THE SANTAI-BEISANTAI AREA OF JUNGGAR BASIN AS AN EXAMPLE

When the oil is suffered from strong biodegradation,most hydrocarbon component(including sterane) is loss,and the common maturity parameters can hardly play their roles.So,how to distinguish the maturity of the strong biodegradation oil is one of the research puzzles.Based the previous research,this paper takes the Santai-Beisantai area of the Junggar Basin for example,analyses the dependability of Ts/Tm.It is pointed out that Ts/Tm increases with maturity and is hard to be biodegraded,and can be used to distinguish the maturity of different type of crude oil.The bitumen and heavy oil derived from the result that the crude oil at low evolutionary stage suffered from loss and strong biode-gradation.The medium density oil comes from the result that oil at mature evolutionary stage suffered from loss and moderate biodegradation.