摘要
本文提出了煤成油气首要的地质、地球化学条件为有利成油的煤相—流水沼泽相。煤中所富含的早期生烃组分(基质镜质体、木栓质体和树脂体等),在R。值为0.35％时即开始生烃,0.6％时已达高峰,0.7％～0.8％时生烃结束;计算表明,煤中微孔对烃类的吸附阀值为86mg/g,煤生烃必需大于该值才有烃类排出;通过对煤的孔隙分布及其对烃类吸附的研究表明,煤成烃最有利的排驱时期在R。为0.8％以前;早期构造、油源断层及区域性盖层是形成煤成油藏的必要条件。
Oil generating is not sharply distinct from coal generation. In fact, during the process of coalification, the hydrogen-rich macerals of coal are undergoing bituminization. In this paper, it is believed that the presence of water-flow (or active) march facies, a coal facies favorable to oil generation is the first important geological and geochemical condition for coal-formed oil and gas. Some enriched macerals in coals, such as degradinite, subrinite and resinite generate hydrocarbons in the early evolutionary stage, i.e. at R_0=0.35%, hydrocarbon generation occurred, at R_0=0.60%, peak of oil generation come forward, in range of R_0=0.7%-0.8%, hydrocarbon generation already ceased. In light of calculation, the adsorption threshold of micro-pores to hydrocarbons is 86 mg/g in coal. If the amount of coal-generated hydrocarbon exceeds this limited value, the surplus will be derived from coal. According to the study of pore distribution pattern and its effects on hydrocarbon adsorption, the most favorable stage for coal-generated hydrocarbon expulsion is prior to R_0=0.8%, and early-existed structures, source-related faults and regional cap beds are essential.
关键词
吐哈盆地
煤层
沉积相
煤成油
初次运移
Turpan-Hami Basin, coal bed, sedimentary facies, liptinite, coal-formed oil, hydrocarbon expulsion
