三塘湖盆地低熟原油成烃机制探讨

DISCUSSION OF THE GENERATION MECHENISM OF IMMATURE OIL IN SANTANGHU BASIN

本文在油源对比的基础上,对三塘湖盆地低熟源岩有机显微组分进行研究,认为盆地主力源岩芦草沟组主要生烃显微组份为腐泥无定型组。该显微组分来源于低等水生生物,由于遭受生物降解而使其丧失颗粒形态,为典型富氢显微组分,具极好生油潜力。并建立了芦草沟组烃源岩生烃演化模式,认为芦草沟组成烃演化明显存在两个生烃高峰,但低成熟的烃源岩决定了其只能完成第一生烃高峰,从而决定了三塘湖盆地为低熟稠油的特征。

On the basis of oil source correlation, the paper studied the organic microscopic component of the immature hydrocarbon source rock in santanghu basin. It is that the major hydrocarbon generating microscopic component of the main source rock of Lucaogou group is a sapropelic amorphous type. The microscopic component come from low-grade aquatic organism have lost its granular shape due to the effect of biological degradation, and it is rich hydrogen with high oil-gas generating potential. From the evolution mode of hydrocarbon source rock hydrocarbon generation of Lucaogou group, It is thought that two hydrocarbon generating peaks are existed in the evolution of Lucaogou group hydrocarbon generation, but only one hydrocarbon generating peak had been completed due to the immature source rock. This determines the characteristics of Santanghu crude to be the immature heavy crude oil.