柴达木盆地北缘侏罗系烃源岩沉积有机相划分及评价

根据柴达木盆地北缘侏罗系烃源岩的有机岩石学、沉积学和有机地球化学特征将烃源岩的沉积有机相划分为4种类型,即高位泥炭沼泽有机相、森林泥炭沼泽有机相、滨浅湖有机相和半深湖-较深湖有机相.在4种沉积有机相类型中,半深湖-较深湖有机相腐泥组含量最高,有机质类型属Ⅰ₂或Ⅰ₁型,生烃性最好并以生油为主;滨浅湖有机相是煤系烃源岩的主体部分,腐泥组含量较低,有机质类型以Ⅱ型和Ⅲ₁型为主,生烃性变化较大,泥岩生烃性中等到差,碳质泥岩大部分生烃性较差;森林泥炭沼泽有机相镜质组含量较高,有机质类型主要为Ⅲ₁型,其生烃性相对较差,以生气为主;高位泥炭沼泽有机相惰质组含量高,有机质类型主要为Ⅲ₂型,其生烃能力最差,以生气为主.

CLASSIFICATION AND ESTIMATION OF ORGANIC FACIES IN JURASSIC SOURCE ROCKS FROM NORTH MARGIN,CHAIDAMU BASIN

The Jurassic hydrocarbon source rocks on the north margin of Qaidam Basin could be divided into highstand marsh peat organic facies, forest marsh peat organic fades, shore-shallow lake organic facies and semideep-deep lake organic facies. The first facies contains high inertinite contents, its organic matter is mainly Ⅲ₂-type, its hydrocarbon-generation capacity is the lowest and gas is the main product; the second facies contains high viitrinite and Ⅲ₁-type organic matter, It hydrocarbon generation capacity is relatively low with gas is the main product; the third facies is primarily coal measures with lower sapropelinite. Its organic' matter is mainly Ⅱ-and Ⅲ₁-types with lower to poor hydrocarbon generation capacity; the last facies has the highest sapropelinite, the organic matter is Ⅰ₂-or Ⅰ₁ types with the best oil generation capacity