塔里木盆地塔中-巴楚地区奥陶系内部存在一期重要的不整合。通过对数十口钻井的地层、古生物研究及与露头剖面的对比,发现该不整合的顶、底层位变化较大,地层缺失量在不同地区有所差异,可大致分为两种情况:其一是塔中地区,上奥陶统良里塔格组覆于鹰山组第三段(下奥陶统上部)之上,且有部分钻井良里塔格组下部也发育不全,缺失了至少11个牙形石带,相当于有17~20Ma的地层缺失;其二是巴楚地区,良里塔格组覆于鹰山组第二段或鹰山组第一段(中奥陶统下部)之上,缺失了至少8个牙形石带,相当于有约14Ma的地层缺失。上述地层缺失主要是由于中奥陶世以后塔里-巴楚地区出水成陆,碳酸盐岩地层受大气淡水溶蚀的结果。在不整合之下碳酸盐岩地层中形成的岩溶是十分重要的油气储层。因此,对该不整合的研究对于塔中、巴楚地区奥陶系,特别是鹰山组的油气勘探具有重要的意义。 There is an important period of unconformity within Ordovician in Tazhong-Bachu area, Tarim Basin. Through the comparison of stratigraphy, paleontology and comparison with outcrop section of dozens of drilling wells, it is found that there is a great change in the top and bottom positions of the unconformity, and the amount of formation loss varies in different regions. There are two kinds of situations: In the Tazhong area, the Upper Ordovician Lianglitage Formation overlies the third member of the Yingshan Formation (upper part of the Lower Ordovician), and some of the lower wells of the Lianglitage Formation are also partially underdeveloped, missing at least 11 The conodont belt is equivalent to the absence of 17 ~ 20 Ma strata. The second is the Bachu area where the Lianglitage Formation overlaps with the second part of the Yingshan Formation or the first paragraph of the Yingshan Formation (lower Ordovician) On the missing at least eight conodont belts, equivalent to about 14Ma of the formation loss. The lack of these formations is mainly due to the discharge of water from the Tarim-Bachu area to the land after the Middle Ordovician, as a result of the carbonate rock formation being eroded by atmospheric fresh water. Karst formation in unconsolidated carbonate formations is a very important oil and gas reservoir. Therefore, the research on this unconformity is of great significance to the exploration of Ordovician, especially Yingshan Formation in Bachu area.