石油学报 ›› 2016, Vol. 37 ›› Issue (1): 43-63.DOI: 10.7623/syxb201601004

• 地质勘探 • 上一篇    下一篇

塔里木盆地塔中地区北坡奥陶系热液蚀变作用

陈红汉1, 鲁子野1, 曹自成2, 韩俊2, 云露2   

  1. 1. 中国地质大学资源学院石油地质系 湖北武汉 430074;
    2. 中国石油化工股份有限公司西北油田分公司 新疆乌鲁木齐 830011
  • 收稿日期:2015-07-13 修回日期:2015-10-30 出版日期:2016-01-25 发布日期:2016-02-02
  • 通讯作者: 陈红汉,男,1962年9月生,1985年获武汉地质学院石油及天然气地质学专业学士学位,现为中国地质大学(武汉)资源学院石油地质系教授、博士生导师,主要从事油气成藏过程研究和流体包裹体系统分析。Email:hhchen@cug.edu.cn
  • 作者简介:陈红汉,男,1962年9月生,1985年获武汉地质学院石油及天然气地质学专业学士学位,现为中国地质大学(武汉)资源学院石油地质系教授、博士生导师,主要从事油气成藏过程研究和流体包裹体系统分析。Email:hhchen@cug.edu.cn
  • 基金资助:

    国家重点基础研究发展计划(973)项目(2012CB214804)和国家重大科技专项(2008ZX05008-003-30)资助。

Hydrothermal alteration of Ordovician reservoir in northeastern slope of Tazhong uplift,Tarim Basin

Chen Honghan1, Lu Ziye1, Cao Zicheng2, Han Jun2, Yun Lu2   

  1. 1. Department of Petroleum Geology, China University of Geosciences, Hubei Wuhan 430074, China;
    2. Sinopec Northwest Oilfield Company, Xinjiang Urumqi 830011, China
  • Received:2015-07-13 Revised:2015-10-30 Online:2016-01-25 Published:2016-02-02

摘要:

沉积盆地超深层(>4500 m)不仅具有与浅层和中深层不同的温压条件,而且流体体制也存在显著差异。以塔里木盆地塔中地区北坡NE向走滑断裂带上的SN4井超深层的中下奥陶统碳酸盐岩硅化段为研究对象,在详细的成岩作用研究基础上,开展了成岩矿物流体包裹体、稳定O-C和Si-O同位素以及常量、微量和稀土元素等系统分析。结果表明,超深层中下奥陶统碳酸盐岩储层存在3种流体端元类型:1深成上升流热液;2外源同生卤水;3这2种热流体与储层同生海水的混合流体。其为经历2种流体-岩石相互作用体制演化的结果:1大气淡水-同生海水重力流演化体制;2火成岩活动驱动远端热液与同生卤水混合上升流演化体制。其中,上升流具有2个流体来源:1受火成岩活动驱动远端热液,具有中低温度、中高盐度、富Si质和富含CO2和H2S挥发份水解成强酸的特征,不仅成为缝洞型储层热液-岩石相互作用的溶剂,而且可能发生了第1期天然气充注;2来源于下伏寒武系烃源岩层的中低温、富Ca和CH4的碱性热卤水,不仅形成了晚期裂缝刀刃状方解石脉,而且发生了第2期天然气充注成藏。依据成岩矿物组合和温度控制矿物学原理构筑其储层化学反应路径模型,结合储层物性测定结果,初步估算这种上升流热液蚀变作用对储层孔隙度的贡献达约8%。由此表明,多期火成岩活动和多期断裂活动不仅为深成上升流提供了动力和通道,而且作为一个独立因素对超深层缝洞型碳酸盐岩储层的形成和天然气的成藏起到了重要的控制作用。综上可推论,塔里木盆地中央火成岩带超深层将是这类热液蚀变缝洞型储层发育带和有利的天然气聚集带。

关键词: 热液蚀变作用, 盆地超深层, 中下奥陶统, 塔中地区北坡, 塔里木盆地

Abstract:

The ultra-deep reservoirs(>4500 m) in the sedimentary basin have different temperature and pressure conditions from shallow and mid-deep reservoirs,and a significant difference also exists in fluid system.The research object is the silicified segment of ultra-deep Middle to Lower Ordovician carbonate reservoirs in Well SN4 along the NE strike-slip faulted belt on northeastern slope of Tazhong uplift,Tarim Basin.Based on deep diagenesis research,systematical analyses were carried out on the fluid inclusion of daigenetic minerals,stable O-C and Si-O isotopes,as well as constant,trace and rare earth elements.The results show that three types of fluid end-members exist in the ultra-deep Middle to Lower Ordovician carbonate reservoirs,i.e.,plutonic upwelling hydrotherm,exogenous syngenetic brine and the mixed fluid of the former two types of fluids and reservoir syngenetic seawater.These three types of fluid end-members evolved from the following two types of fluid-rock interaction system,i.e.,the evolution system of meteoric water-syngenetic seawater gravity flow and that of remote hydrotherm-syngenetic brine mixed upwelling flow driven by igneous activities.The upwelling flow has two fluid sources,i.e.,(1) remote hydrotherm driven by igneous activities,characterized by mid-low temperature,mid-high salinity,rich Si and strong acidity resulting from CO2 and H2S hydrolysis reactions,which is the solvent generated in interaction between fractured-vuggy reservoir hydrotherm and rock,and may induce the first phase of natural gas charging;(2) the hot alkaline brine with mid-low temperature,rich in Ca and CH4,and sourced from the underlying Cambrian source rocks,leading to the formation of late fissure-type bladed calcite and the second phase of natural gas charging for accumulation.Based on diagenetic mineral assemblages and temperature control mineralogy principle,the path model of chemical reaction in reservoirs was created.In combination with the measurements of reservoir physical properties,it was preliminarily estimated that the alternation of such upwelling hydrotherm contributed 8% to reservoir porosity.Therefore,it is indicated that multi-phase igneous activities and fault movements could provide driving force and access for upwelling hydrotherm.Meanwhile,it is an independent factor that plays a very important role in controlling the formation of ultra-deep fractured-vuggy carbonate reservoirs and natural gas accumulation.It is concluded that the central igneous zone in Tarim Basin will become the development zones of hydrothermal fractured-vuggy reservoirs and favorable natural gas accumulation zones.

Key words: hydrothermal alteration, ultra-deep basin, the Middle to Lower Ordovician, northeastern slope of Tazhong uplift, Tarim Basin

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