摘要
本文对新疆准噶尔盆地南缘二叠系芦草沟组及陕甘宁盆地彬县三叠系油页岩进行了系统的有机地球化学研究,并探讨了油页岩所生成的烃类的初次运移早期阶段的分异作用和运移机理.
This paper deals with the study on geochmistry of Xinjiang oil shale (P2l) in the south Junggar Basin ana Shaanxi oil snales (T3y) in the south Shaanganning basin (shaanxi-Gansu-Ningxia), China, and the fractionation of their compounds during early primary migration.
Geochmistry of the oil shales
The results show that the organic matter of Xinjiang and Shaanxi oil shales are type Ⅱ2-Ⅲ .Therm a simulation experiment of the kerogens shows that Xinjiang and Shaanxi oil shales are mainly generating gas hydrocarbons, the most productivities are 201.71 and 226.13m3/ T, restectively.The values arc as much as that of Kedu browncoal (289.00m3 / T), Yunnan, The liquid hydrocarbon arc a little.The most prod uctivities are 6.4% and 4.4%, respectively.
According to the Ro, O/ C atomic ration, OEP and CPI, MPI and DPI, and the parameters of biomarkers, Xinjiang and Shaanxi oil shales are at early matural stage.
Molecular fractionations during early primary migration for the oil shales Xinjiang and Shaanxi oil shales have been studied with the stepwise extraction technique by S. N. Beltskaya (1970) .The extract o.f 'closed'pores represents original organic matter, not migrating, and the extract of 'open'pores the migrating, from 'closed'pores.the following results have been concluded:
1) The content of low molecular weight alkanes is higher in the open pores than that in the pores, but high molecular weight alkanes lower in the closed pores, but high molecular weigh; lower in the open pores than that in the closed pores.This means that lower molecular weigh; be migrated easily; 2) The contents of steranes and hopanes with the same molecular weights struction but different configuration, are not different obviously in the open pores and closed n Aromatic hydrocarbon study shows that β- methylphenanthrene can be migrated more α-methylphenanthrene and 9- methylphenanthrene from the closed pores to the open pores, ββ-dismcthylphenanthrene more easily thanα, α-, α, β- and β (α), 9-dismcthylphcnanihrenc mono-ring aromatic compounds more easily than dis-ring aromatic compounds; 4) The compounds containing oxygen atom can be easily moved from the closed pores to the open pores.The cause may be ucd to the surface characters of the rocks, The roles of the fractionation effects arc below:
The fractionation effects of molecules during early primary migration vary with size and shape, and molecular polarity; The surface character of source rocks also influences tion fractionation.
The mechanism of the migration may tied to the diffusion effects of molecules and the surface character of rocks.
The study suggests that the hydrocarbons generated in the oil shales could migrate, at least in distance.
出处
《沉积学报》
CAS
CSCD
北大核心
1989年第3期99-104,共6页
Acta Sedimentologica Sinica
