石油学报 ›› 2020, Vol. 41 ›› Issue (2): 179-196.DOI: 10.7623/syxb202002004

• 地质勘探 • 上一篇    下一篇

高原咸化湖盆基底储层特征与成藏主控因素——以柴达木盆地东坪地区为例

黄成刚1, 张小军1, 胡贵2, 刘应如1, 张希文2, 张国辉2, 李红哲1, 吴梁宇1   

  1. 1. 中国石油勘探开发研究院西北分院 甘肃兰州 730020;
    2. 中国石油勘探开发研究院 北京 100083
  • 收稿日期:2018-12-16 修回日期:2019-09-12 出版日期:2020-02-25 发布日期:2020-03-09
  • 通讯作者: 黄成刚,男,1979年2月生,2001年获江汉石油学院石油地质勘察专业学士学位,2004年获成都理工大学矿物学、岩石学、矿床学专业硕士学位,现为中国石油勘探开发研究院西北分院高级工程师,主要从事沉积储层与地球化学方面的研究工作。Email:12664018@qq.com
  • 作者简介:黄成刚,男,1979年2月生,2001年获江汉石油学院石油地质勘察专业学士学位,2004年获成都理工大学矿物学、岩石学、矿床学专业硕士学位,现为中国石油勘探开发研究院西北分院高级工程师,主要从事沉积储层与地球化学方面的研究工作。Email:12664018@qq.com
  • 基金资助:

    国家科技重大专项"柴达木盆地复杂构造区油气成藏、关键勘探技术与新领域目标优选"(2016ZX05003)和中国石油天然气股份有限公司科技重大项目"柴达木盆地建设高原大油气田勘探开发关键技术研究与应用"(2016E-0101)资助。

Reservoir characteristics and main controlling factors of hydrocarbon accumulation of basement in plateau saline lacustrine basin: a case study of Dongping area in Qaidam Basin

Huang Chenggang1, Zhang Xiaojun1, Hu Gui2, Liu Yingru1, Zhang Xiwen2, Zhang Guohui2, Li Hongzhe1, Wu Liangyu1   

  1. 1. Northwest Branch of PetroChina Research Institute of Petroleum Exploration and Development, Gansu Lanzhou 730020, China;
    2. PetroChina Research Institute of Petroleum Exploration and Development, Beijing 100083, China
  • Received:2018-12-16 Revised:2019-09-12 Online:2020-02-25 Published:2020-03-09

摘要:

近年来,高原咸化湖盆基底的天然气勘探持续获得了重大发现。为了系统分析柴达木盆地东坪地区基岩大气田的储层特征与成藏主控因素,开展了钻井岩心观察、偏光显微镜鉴定、物性分析、毛细管压力测试、氩离子抛光-场发射扫描电镜研究、地震剖面解释和成藏模式刻画。研究结果表明:①基岩主要由花岗岩和片麻岩组成,花岗岩类主要为I型,含少量S型,平均孔隙度为3.49%,平均渗透率为1.389 mD,其孔隙结构较差,非均质性较强,储集空间包括基质微孔、溶蚀孔和微裂缝等;②基岩中的溶蚀孔主要为热液成因,判断依据包括溶蚀孔发育位置、裂缝中发育的大量热液矿物、岩石的Nb/Ta值接近或低于幔源岩石和Nd/Th值介于壳源岩石和幔源岩石之间、地震剖面上发育深大断裂等;③膏岩盖层的局部富集特征与大气藏的分布具有较高的吻合度;④良好的生-储-盖条件为研究区持续高产、稳产的主控因素;⑤逆冲推覆作用产生的逆断层不仅为油气运移通道,而且将下伏的储集岩叠置于上覆的烃源岩之上,优化了源储配置,更利于油气成藏。咸化湖盆沉积的膏岩盖层的有效性、热液溶蚀作用形成的储集空间规模和逆冲推覆作用优化的源储组合为研究区基岩油气成藏的主控因素,这一研究实例对类似地质条件的油气勘探也具有一定的借鉴意义。

关键词: 基岩气田, 热液溶蚀, 基质微孔, 油气成藏条件, 东坪地区, 高原咸化湖盆, 柴达木盆地

Abstract:

In recent years,significant and sustained discoveries have been made in natural gas exploration of the basement of plateau saline lacustrine basin. In order to systematically analyze the reservoir characteristics and main controlling factors of hydrocarbon accumulation of the bedrock gas field in Dongping area of Qaidam Basin,drilling core observation,polarizing microscope identification,physical characteristic analysis,capillary pressure test,Argon ion polishing and field emission scanning electron microscopy,seismic profile interpretation and hydrocarbon accumulation model characterization were carried out. The results show that:(1)The bedrock is mainly composed of granite and gneiss,and the granite is mainly I-type,with a small amount of S-type,with an average porosity of 3.49%,an average permeability of 1.389 mD,poor pore structure and strong heterogeneity. The reservoir space includes matrix micropore,dissolution pore and micro-fracture. (2)The dissolution pore in bedrock is mainly hydrothermal origin. The judgment basis includes the location of dissolution pore,a large number of hydrothermal minerals developed in fractures,the Nb/Ta value of rocks close to or lower than that of mantle-derived rocks and the Nd/Th value between crust-derived rocks and mantle-derived rocks,and the development of deep faults in seismic profiles. (3) These are high coincidence between the local enrichment characteristics of gypsum caprock and the distribution of large gas reservoirs. (4)Good source-reservoir-capping conditions are the main factors controlling the sustained high and stable production in the study area. (5)The thrust faults generated by thrusting nappe are not only hydrocarbon migration pathways,but also superimpose underlying reservoirs on overlying source rocks,which optimize the source-reservoir allocation and are more conducive to hydrocarbon accumulation. The main controlling factors of hydrocarbon accumulation in bedrock of the study area are effectiveness of gypsum caprock deposited in saline lake basin,scale of reservoir space formed by hydrothermal dissolution and optimized source-reservoir combination of thrust nappe. This research has a certain significance for in oil and gas exploration under similar geological conditions.

Key words: bedrock gas field, hydrothermal solution, matrix micropore, hydrocarbon accumulation conditions, Dongping area, plateau saline lacustrine basin, Qaidam Basin

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