塔里木盆地塔中—巴楚地区奥陶系内幕不整合  

Unconformities in the Ordovician of Tazhong—Bachu Area of the Tarim Basin,NW China

作　　者：邓胜徽[1,2,3] 杜品德[4] 卢远征[1,2,3] 黄智斌[4] 景秀春[5] 张师本[1,4] 樊茹[1,2,3] 杨芝林[4] 李鑫[1,2,3] 

机构地区：[1]中国石油天然气股份有限公司勘探开发研究院,北京100083 [2]中国石油天然气集团公司提高石油采收率国家重点实验室,北京100083 [3]中国石油天然气集团公司油气储层重点实验室,北京100083 [4]中国石油天然气股份有限公司塔里木油田公司勘探开发研究院,新疆库尔勒841000 [5]中国地质大学(北京),北京100083

出　　处：《地质论评》2015年第2期324-332,共9页Geological Review

基　　金：中国石油塔里木油田公司项目;中国石油勘探开发研究院中青年创新基金项目;国家重大科技专项课题(课题号2011ZX05004-002);中国石油天然气股份有限公司"十二五"重点项目(课题号2014A-0216)的成果

摘　　要：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 excited an unconformity between the Lower--Middle Ordovician Yingshan Formation and its overlying strata in Tazhong--Bachu area of the Tarim basin, Northwest China. Systematic and detailed studies on conodont fauna indicate that the strata under the unconformity have various ages in different areas, and the strata over the unconformity is nearly the same horizon, namely the Lianglitag Formation of Upper Ordovician. In Tazhong area, the Lianglitag Formation is directly over the Member 3 of the Yingshan Formation, which indicates that the absent strata include the Members 1 and 2 of the Yingshan Formation, the Yijianfang Formation, the Tumuxiuk Formation; and partially the lowermost of the Lianglitag Formation. This stratigraphical lacuna equals to 11 conodont biostratigraphical zones at least, which is inferred to be an interval of about 17 -20 Ma long. In Bachu area, west of Tazhong area, the Lianglitag Formation is underlain by the Member 2 or even Member 1 of the Yingshan Formation, which implicates that the strata lost in the unconformity is less than that of Tazhong area. The lost strata equals to at least 8 conodont zones, indicating a stratigraphical lacuna of 14 Ma. This unconformity is important for the development of the karst reservoirs in the Yingshan Formation and is significant for the oil--gas exploration in the Ordovician of the Tarim basin.

关 键 词：奥陶系 不整合面 地层缺失量 油气勘探意义 塔里木盆地 

分 类 号：P618.13[天文地球—矿床学]