塔里木盆地寒武－奥陶系生油岩成油期─－兼谈喜山晚期“二次生油”

STUDY ON THE OIL-FORMING PERIODS OF CAMBEO-ORDOVICIAN SOURCE ROCKS IN THE TARIM BASIN AND ALSO ON THE SECONDARY GENERATION OF OIL IN THE LATE HIMALAYAN EPOCH

寒武－奥陶系生油岩是塔里木盆地主力油源，尤以满加尔坳陷发育最佳。本文以基础数据为依据，主要论述该套烃源岩的成油期问题，认为寒武系生油岩主成油期为古生代，并在中新生代具二次生油特点；奥陶系生油岩主成油期为海西晚期（满加尔坳陷）和中新生代。塔北、塔中诸多高产油气田中的油气主要为中新生代所形成。

The Cambro-Ordovician systems of Tarim Basin, with regional extent,large thick-ness,high organic content and good type of organic matter,are the primary contributor to the hydrocarbons generated in Tarim,especially in Manjiar Depression.The main period of petroleum generation of Cambrian source rocks was in Pale-ocene,and the secondary generation of oil also occurred from late Yanshan to early Hi-malayan Epoch.The oil-generating period of Ordovician source rocks,however,changed in regions,late Hercynian for Manjiar Depression and Mesozoic for the outer areas of the eastern Tarim. The fault-block buried-hill type traps and draping anticline-type traps in Mesozoic strata were consistent with oil-generating phase of Ordovician source rocks and the sec-ondary generation of Cambrian hydrocarbons.That's why the exploration of these two kinds of traps,which are the dominant sites of petroleum accumulations found in Tarim up to now,meets with great success.