石油学报 ›› 2012, Vol. 33 ›› Issue (5): 748-757.DOI: 10.7623/syxb201205003

• 地质勘探 • 上一篇    下一篇

塔里木盆地哈6井石炭系、志留系砂岩自生伊利石K-Ar、Ar-Ar测年与成藏年代

张有瑜 1,2 罗修泉 1   

  1. 1 中国石油勘探开发研究院 北京 100083;2 中国石油天然气股份有限公司盆地构造与油气成藏重点实验室 北京 100083
  • 收稿日期:2011-12-14 修回日期:2012-04-08 出版日期:2012-09-25 发布日期:2012-11-27
  • 通讯作者: 张有瑜
  • 作者简介:张有瑜,男,1955年8月生,1982年获中南大学学士学位,1988年获中国地质大学(北京)硕士学位,现为中国石油勘探开发研究院教授级高级工程师,主要从事油气储层自生伊利石K-Ar测年、He、Ar同位素质谱分析、常规K-Ar、Ar-Ar测年和含油气盆地黏土矿物研究。
  • 基金资助:

    国家重点基础研究发展计划(973)项目“中国西部典型叠合盆地油气成藏机制与分布规律”(2006CB202300)资助。

K-Ar and Ar-Ar dating of authigenic illite and hydrocarbon accumulation history of Carboniferous and Silurian sandstone reservoirs in Well Ha 6, Tarim Basin

ZHANG Youyu 1,2 LUO Xiuquan 1   

  • Received:2011-12-14 Revised:2012-04-08 Online:2012-09-25 Published:2012-11-27

摘要:

利用自生伊利石K-Ar、Ar-Ar测年技术对塔里木盆地哈6井石炭系、志留系砂岩油气藏的成藏年代进行测定与研究。哈6井石炭系角砾岩段自生伊利石K-Ar年龄为86 Ma,相当于晚白垩世,表明为燕山晚期成藏;志留系沥青砂岩自生伊利石K-Ar年龄为125 Ma,相当于早白垩世晚期,表明为燕山中晚期成藏。石炭系、志留系砂岩是塔里木盆地的重要储层,广泛分布于塔中隆起、北部坳陷和塔北隆起,已知的自生伊利石年龄范围分别是:石炭系东河砂岩为231~285 Ma,志留系沥青砂岩为204~383 Ma。与塔里木盆地其他地区相比,本次研究的哈6井石炭系、志留系砂岩的自生伊利石年龄明显偏小,表明哈6井石炭系、志留系油气藏的成藏期明显偏晚,对其勘探意义应该开展深入研究。哈6井石炭系、志留系砂岩自生伊利石的Ar-Ar年龄分别为148~159 Ma和189~195 Ma,与其K-Ar年龄相比明显偏老,可能不具有明确的地质意义,更不能反映油气注入事件和代表成藏期,快中子照射过程中的 39Ar 反冲丢失是其主要原因。

关键词: 塔里木盆地, 哈6井, 石炭系、志留系砂岩, 自生伊利石, K-Ar、Ar-Ar测年, 成藏年代

Abstract:

The hydrocarbon charge history of Carboniferous-Silurian sandstone reservoirs in Well Ha 6, Tarim Basin, was comprehensively studied by applying SEM observation, clay mineral XRD characterization, illite genetic type identification and the K-Ar and Ar-Ar dating of authigenic illite. The result shows that the authigenic illite K-Ar age of Carboniferous sandstone reservoirs in Well Ha 6 is 86 Ma, corresponding to Late Cretaceous and indicating the primary formation of the Carboniferous oil pool mainly in the late Yanshanian period, while the authigenic illite K-Ar age of Silurian bituminous sandstone reservoirs in Well Ha 6 is 125 Ma, corresponding to a late stage of Early Cretaceous and indicating the primary formation of the Silurian oil pool mainly in the middle to late Yanshanian period. Carboniferous-Silurian sandstones are one of the important reservoirs in Tarim Basin and they are well developed in Tazhong uplift, the northern depression and Tabei uplift. Their dated authigenic illite ages range from 231 Ma to 285 Ma for the Carboniferous Donghe sandstone and from 204 Ma to 383 Ma for the Silurian Bituminous sandstone, respectively. Compared with authigenic illites in other major regions of Tarim Basin, the age of authigenic illites in the Carboniferous-Silurian sandstones from Well Ha 6 is obviously young, indicating that the accumulation of Carboniferous-Silurian pools in Well Ha 6 occurred more lately, therefore, detailed investigations on the implication of this occurrence in oil exploration should be conducted as well. Authigenic illite Ar-Ar ages of the Carboniferous and Silurian sandstone reservoirs in Well Ha 6 are 148~159 Ma and 189~195Ma, respectively, appearing much older than the corresponding K-Ar ages, which indicates that the Ar-Ar ages probably have no definite geological meanings, and can not be representative of the hydrocarbon charging time. The 39Ar recoil loss during neutron irradiation seems the main reason for these older Ar-Ar ages.

Key words: Tarim Basin, Well Ha 6, Carboniferous-Silurian sandstone, authigenic illite, K-Ar/Ar-Ar dating, accumulation time