石油与天然气地质 ›› 2007, Vol. 28 ›› Issue (6): 802-808.doi: 10.11743/ogg20070615

• 论文 • 上一篇    下一篇

塔中奥陶系地层水化学特征及其成因与演化

李鹏春1,2,3, 刘春晓1,2,4,5, 张渊2, 龙利平2, 张利红2   

  1. 1. 中国科学院 海洋研究所,山东 青岛 266071;
    2. 中国石油化工股份有限公司 中原油田分公司 物探研究院,河南 濮阳 457001;
    3. 中国科学院 地质与地球物理研究所,北京 100029;
    4. 中国科学院 研究生院,北京 100049;
    5. 中国石油大学,山东 东营 257000
  • 收稿日期:2007-10-14 出版日期:2007-12-25 发布日期:2012-01-16
  • 基金项目:

    中国石油化工股份有限公司科技攻关项目(2007115)

Geochemical behaviors of the Ordovician formation water in the Tazhong area and its origin and evolution

Li Pengchun1,2,3, Liu Chunxiao1,2,4,5, Zhang Yuan2, Long Liping2, Zhang Lihong2   

  1. 1. Research Institute of Marine Geology, Chinese Academy of Sciences, Qingdao, Shandong 266071, China;
    2. Research Institute of Geophysical Prospecting, Zhongyuan Oilfield Company, SINOPEC, Puyang, Henan 457001, China;
    3. Graduate School, Chinese Academy of Sciences, Beijing 100049, China;
    4. Research Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China;
    5. China University of Petroleum, Dongying, Shandong 257000, China
  • Received:2007-10-14 Online:2007-12-25 Published:2012-01-16

PDF (PC)

663

被引次数

24

摘要：

塔中地区奥陶系地层水化学组成以(K++Na+),Cl-离子为主,大部分为CaCl2型水,矿化度变化介于4.8～220.2g/L,rNa+/rCl-比值变化介于0.26～0.85之间,说明变质程度小,可能是海水发生蒸发浓缩作用之后被淡水所混合的产物。受断裂作用影响,地层水矿化度在平面上具有明显的分区性;受区域不整合影响,纵向上地层水离子浓度和矿化度存在明显的分带性。地层水中阴离子Cl-和HCO3-的浓度与阳离子(Na++K+)和Ca2+的浓度的关系表明,本区可能的成岩作用过程主要为氯化钠矿物和碳酸盐矿物的溶解作用,而方解石的(铁)白云石化及钠长石化作用导致了Ca2+离子的富集与Mg2+离子的亏损,形成了CaCl2型流体。区内地层水可分为常压高矿化度水和异常高压低矿化度水两种类型。前者可能与大气淡水淋滤和埋藏过程中的水-岩相互作用有关,后者可能与其形成的封闭体系有关。油气聚集和保存条件较好的区域位于塔中Ⅰ号坡折带和Ⅱ号构造带之间。

关键词: 流体-岩石相互作用, 成因与演化, 地层水化学特征, 奥陶系, 塔中地区

Abstract:

Chemical compositions of the Ordovician formation water in Tazhong area are dominated by cations as K+ + Na+ and anions like Cl-.The water is mostly of CaCl2 type with salinity ranging from 4.8 to 220.2 g/L and rNa+/rCI- ratio varing between 0.26 and 0.85,suggesting a small change of water property and a possible origin from mixing of fresh water with sea water after evaporation and inspissation.Influenced by fracturing effect, the plane distribution of formation water salinity is characterized by obvious regionalization ;while affected by regional unconformities,the vertical distribution of ion concentration and salinity is featured in zonation.The relationship between cation concentration of Cl- and HCO3- and anion concentration of Na+ + K+ and Ca2+ indicated that the likely diagenesis process in the study area was mainly dissolutions of NaC1 and carbonate,and that the dolomitization(ferrodolomite)and albitization of calcite resulted in excess of Ca2+ and deficit of Mg2+, forming CaCl2-type fluid.Formation water in the area can be classified into two groups:normal-pressure high-salinity water and abnormal high-pressure low-salinity water.The former may be related the leaching of atmospheric water and to the water-rock interaction during burial,while the latter may be connected with the closed system formed by the type of water itself.The area between TZ-Ⅰ slope break and TZ-Ⅱ structural zone is considered to have favorable conditions for accumulation and preserving of hydrocarbons.

Key words: fluid-rock interaction, origin and evolution, geochemical behavior of formation water, Ordovician, Tazhong area

中图分类号: