塔中地区奥陶系烃源岩显微荧光特征及排烃期

MICROFLUORESCENCE CHARACTERISTICS AND EXPELLING HYDROCARBON PERIOD OF ORDOVICIAN SOURCE ROCK IN TAZHONG AREA.

通过对塔中１２井奥陶系碳酸盐岩的显微荧光特征分析并结合成岩作用研究，认为塔中地区奥陶系烃源岩有二次排烃期和较高的生烃潜量，第一次排烃发生在早成岩阶段以低成熟的重烃排出为主；第二次发生在晚成岩阶段以成熟的轻烃排出为主。此外，对排烃时间与相应的构造运动关系进行了尝试性探讨：下奥陶统烃源岩第一期排烃发生在加里东运动中期；中－上奥陶统烃源岩第一期排烃发生在晚海西运动前后；两层系的第二期排烃均发生在喜马拉雅期至今。

On the basis of microfluorescence characteristics analysis and diagenesis study of carbonate rock inOrdovician in Well Tazhong 12, we found that there are two expelling hydrocarbon periods and higher hydrocarbon generation potential in Ordovician source rock in Tazhong area, and the first expelling hydrocarbon occurred in early diagenesis stage dominated by heavy hydrocarbon with low maturity, the second one in late diagenesis stage dominated by mature light hydrocarbon. In addition, attemped discussion of the relatios between expelling hydrocarbon time and corresponding tectonic movement has been made, drawing the conclusion that the first expelling hydrocarbon of Lower Ordovician source rock occurred in middle period of Caledonian orogeny; the first expelling hydrocarbon of Mid Upper Ordovician source rock in about late Hercynian orogeny; the second expelling hydrocarbon of Lower and Mid Upper Ordovician source rock in Himalayan orogeny till now.