大杨树盆地原油显示及其地球化学特征

大杨树盆地位于内蒙古自治区东部的阿荣旗与鄂伦春自治旗境内，大地构造上属于内蒙一兴安岭褶皱系，兴安岭皱带的示部，为一北东东向长条状展布的中新生断陷盆地，面积为１５４６０km^2，沉积岩最大埋深为３２００m。

Geochemical characteristics of crude oil in Dayangshu basin

According to analyses of carbon number distribution of n-alkane, component carbon isotope, monomer hydrocarbon carbon isotope, biological marker and so on,the geochemical characteristics and origin of crude oil of Well Yang-D1 in Dayangshu basin was studied. The results show that content of saturated hydrocarbon is higher; both contents of aromatic hydrocarbon and non-hydrocarbon are lower in the crude oil component. Carbon number distribution of n-alkane shows that the crude oil of Well Yang-D1 is mature oil. Component carbon isotope of the oil is higher, and both component carbon isotopes of aromatic hydrocarbon and non-hydrocarbon are 5% higher than that of the crude oil of Songliao basin. Monomer hydrocarbon carbon isotope of the crude oil is generally－29‰. The distribution of monomer hydrocarbon carbon isotope shows that the component with carbon number less than 21 are mainly derived from bacteria and algae, and the component with carbon number more than 21 are mainly derived from higher plants. Biological marks of the crude oil contain long lateral chain of tricyclic terpane, and the content of gammacerane is low. The mature parameters of C2920S/20 (S+R) and C29ββ/ (αα+ββ) are respectively 0.46 and 0.49, showing features of mature oil. Synthetic analytic result shows that oil of Well Yang-D1 is mature oil that was generated by humic type organic matter, and has obvious migration effect. From geology and geochemical characteristics of the basin, the authors hold that oil of Well Yang-D1 is probably derived from Jiufengshan Formation of Upper Jurassic.