地学前缘 ›› 2023, Vol. 30 ›› Issue (1): 81-105.DOI: 10.13745/j.esf.sf.2022.8.35

• 构造控油理论与勘探开发新领域 • 上一篇    下一篇

青海共和盆地结构构造与能源资源潜力

何碧竹1,2(), 郑孟林3, 贠晓瑞1,4,5, 蔡志慧1, 焦存礼5, 陈希节1,6, 郑勇1,2, 马绪宣1,2, 刘若涵1,7, 陈辉明1, 张盛生8, 雷敏1, 付国强9, 李振宇1,4   

  1. 1.中国地质科学院 地质研究所 自然资源部深地动力学重点实验室, 北京 100037
    2.南方海洋科学与工程广东省实验室, 广东 广州 511458
    3.中国石油新疆油田分公司勘探开发研究院, 新疆 克拉玛依 834000
    4.中国地质大学(北京), 北京 100083
    5.中国石化勘探开发研究院, 北京 100083
    6.中国地质调查局 发展研究中心, 北京 100037
    7.中国石油勘探开发研究院, 北京 100083
    8.青海省水文地质工程地质环境地质调查院, 青海 西宁 810008
    9.中国矿业大学, 江苏 徐州 221116
  • 收稿日期:2022-07-07 修回日期:2022-08-05 出版日期:2023-01-25 发布日期:2022-10-20
  • 作者简介:何碧竹(1965—),女,研究员,博士生导师,主要从事盆地构造分析、油气勘探目标及干热岩地热能资源评价研究。E-mail: hebizhu@cags.ac.cn;hebizhu@vip.sina.com
  • 基金资助:
    国家自然科学基金项目(41872121);国家自然科学基金项目(41630207);国家自然科学基金项目(4217226);南方海洋科学与工程广东省实验室(广州)人才团队引进重大专项(GML2019ZD0201);中国地质科学院基本科研业务项目(A1903);中国地质科学院基本科研业务项目(JYYWF20180903);中国地质调查局项目(DD20221649);中国地质调查局项目(DD20190006);中国地质调查局项目(DD20190060);中国地质调查局项目(DD2019013);青海省重点研发计划项目(2018-SF-109)

Structural architecture and energy resource potential of Gonghe Basin, NE Qinghai-Tibet Plateau

HE Bizhu1,2(), ZHENG Menglin3, YUN Xiaorui1,4,5, CAI Zhihui1, JIAO Cunli5, CHEN Xijie1,6, ZHENG Yong1,2, MA Xuxuan1,2, LIU Ruohan1,7, CHEN Huiming1, ZHANG Shengsheng8, LEI Min1, FU Guoqiang9, LI Zhenyu1,4   

  1. 1. Key Laboratory of Deep-Earth Dynamics of Ministry of Natural Resources, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China
    2. Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou 511458, China
    3. Petroleum Exploration and Development Institute, Xinjiang Oilfield Company, PetroChina, Karamay 834000, China
    4. China University of Geosciences(Beijing), Beijing 100083, China
    5. Exploration and Production Research Institute of SINOPEC, Beijing 100083, China
    6. Development and Research Center of China Geological Survey, Beijing 100037, China
    7. PetroChina Research Institute of Petroleum Exploration & Development, Beijing 100083, China
    8. Qinghai Survey Institute of the Hydrogeology and Engineering & Environmental Geology, Xining 810008, China
    9. China University of Mining and Technology, Xuzhou 221116, China
  • Received:2022-07-07 Revised:2022-08-05 Online:2023-01-25 Published:2022-10-20

摘要:

共和盆地处于西秦岭、南祁连、东昆仑造山带结合部,其中发现了高温干热岩及多套烃源岩,但地热藏和油气藏的成因、资源潜力与分布规律尚不清楚,难以对其开展准确评价和有效勘探开发。本文在系统研究共和盆地及周缘地层发育、沉积充填、构造变形与盆地深部结构的基础上,深入探讨了盆地演化的动力学机制,分析了盆地地热藏和油气藏的成藏主控因素,预测了有利分布区带和勘探方向。多期活动的哇洪山—温泉、多禾茂、瓦里贡、塘格木右行走滑逆冲断裂与青海南山左行走滑逆冲断裂异向、同向相交(切),叠加地幔上涌作用,导致在中新生代共和盆地长期处于走滑-伸展的独特环境,并控制了盆地7个隆起、断陷构造单元的展布及属性。它经历了6期演化阶段:早中三叠世处于昆北弧前盆地及陆缘火山弧带,共和盆地基底主要岩石发育;晚三叠世阿尼玛卿洋闭合并发生碰撞造山,共和盆地褶皱基底形成;晚三叠纪末期发生碰撞后伸展,发育初始小型陆内裂谷盆地;在侏罗纪—白垩纪区域性伸展环境下形成局部断陷盆地;古近纪晚期—中新世发育拉分-断陷盆地;中新世末至今发育陆内前陆盆地。形成了3个大构造-沉积层序和8个亚层序,发育了深海陆棚相-碳酸盐岩台地相-火成岩相以及多旋回的冲积扇-河流相-滨浅湖相-半深湖相等陆相沉积层序,它们记录了共和盆地的叠合发育演化及多期改造过程,与古特斯阿尼玛卿洋俯冲、后撤式俯冲、碰撞后伸展的近程效应响应,与班公-怒江、雅鲁藏布江新特提斯洋打开、俯冲、闭合以及印度/欧亚大陆碰撞过程的远程效应响应。
共和盆地构造-沉积演化特色造就了盆地较好的油气和地热的能源资源条件。盆地发育有中下侏罗统羊曲组、下白垩统万秀组、新近系咸水河组和临夏组等三套烃源岩,可形成上-中-下三套潜力油气勘探层系,需进一步开展地层精细对比、区带评价和圈闭落实工作。共和盆地深部5层结构构造特征及盆地形成动力学过程揭示了其具有丰富的地热能资源潜力。幔源上涌驱动导致地壳内各层向上扰动,叠加走滑伸展的盆地发育环境,形成短路径-多源增热模式。地幔上涌、中下地壳局部熔融体提供了区域热源、局部热源;陆缘弧和碰撞相关花岗岩类叠加多期次断裂、裂缝及热液活动起到“控热储及热传导”作用;上覆巨厚细粒沉积岩阻热扩散而形成“控热盖”,是中高温干热岩型地热藏主控因素,也为浅层水热型地热的生成奠基。研究成果可为存在局部高大地热流的陆内中小型盆地地热藏研究提供借鉴。

关键词: 构造-地层层序, 深部结构构造, 演化与动力学, 短路径-多源增热模式, 干热岩地热能, 油气资源潜力, 共和盆地

Abstract:

The Gonghe Basin is located at the junction of the South Qilian, East Kunlun and West Qinling orogenic belts in the NE Qinghai-Tibet Plateau where high temperature Hot Dry Rocks and multiple sets of source rocks are discovered. However, without a clear understanding of the genesis, resource potential and distribution pattern of geothermal and oil and gas reservoirs, it is difficult to carry out accurate resource evaluation and effective resource exploration and development in the Gonghe Basin. In this study, the regional tectono-sedimentary sequences, deep tectonic architecture and tectonic deformation are systematically analyzed, the dynamic process of basin evolution is discussed, the main factors controlling reservoir formation in geothermal and hydrocarbon accumulation are analyzed, and the favorable distribution zones and exploration directions are proposed. In the Gonghe Basin, the periodically active Wahongshan-Wenquan, Tanggemu, Waligong and Duohemao NNW-striking dextral strike-slip and thrust faults and the Qinghai Nanshan NWW(E-W)-striking thrust and sinistral strike-slip fault intersect (or in tangent) in the same or opposite direction, and the superposition of the intersecting faults and mantle upwelling result in the unique strike-slip stretching environment during most of the Cenozoic, and control the distribution and properties of seven tectonic units featuring faulted-depressions and uplifts. The Gonghe Basin region experienced six stages of evolution: 1) Development of main basement rock in the Early-Middle Triassic in the northern parts of East Kunlun forearc basin and volcanic arc belt; 2) Collision orogeny and formation of folded basement in the Late Triassic; 3) Post-collisional extension and development of local continental facies in prototype basin at the end of Triassic; 4) Formation of local faulted depressions in the Jurassic-Cretaceous under regional extension; 5) Development of strike-slip pull-apart and faulted basin in the Late Paleogene-Miocene; and 6) Development of intracontinental foreland basins in the Pliocene to the present. During the Meso-Cenozoic periods three large tectonic-sedimentary sequences and eight secondary sequences are formed in the Gonghe Basin, along with the developments of the deep-water shelf and carbonate platform facies, igneous facies, as well as the multi-cyclic terrestrial sedimentary sequences of the alluvial-fluvial, littoral-shallow lacustrine and semi-deep lacustrine facies. The superimposed evolutionary processes record the basin response to the near field effects of the northward subducting, retraction-subducting, and post-collisional extension of the Anemaqen Paleotethyan ocean slab, and to the remote effects of the opening, subducting and closure of the Neotethyan Ocean and the India-Eurasia continental collision.
The unique tectono-sedimentary evolution results in the favorable oil/gas and geothermal energy resources conditions in the Gonghe Basin, where three sets of hydrocarbon source rocks are developed in the Lower Jurassic, Lower Cretaceous and Neogene, and they can—pending further fine correlation, play evaluation and favorable trap confirmation—form three favorable oil and gas exploration strata. The five-layer deep structural architecture of the Gonghe Basin and its genetic dynamics reveal the basin’s favorable geothermal resources potential. Mantle upwelling leads to the upward movements of each layer in the crust, which results in the short-path, multi-source heating action under the strike-slip and extensional development environment of the basin. The Hot Dry Rock geothermal reservoirs are formed in the basin’s fault intersection zones. For the medium-high temperature reservoirs the main controlling factors are: mantle upwelling and lower-middle crustal partial melting respectively providing the regional and local heat sources; continental margin arc and collision-related granitoids, superimposed with multi-stage fault, fracture and hydrothermal activities, controlling the heat storage and heat conduction; and the thermally stable overlying ultra-thick fine-grained sedimentary rock layers providing the reservoir caps. These factors may also control the heat source and heat conduction in shallow hydrothermal geothermal reservoirs. This study provides a reference for the understanding of geothermal reservoirs in small-medium size intracontinental basins with locally high terrestrial heat flows.

Key words: tectono-stratigraphic sequences, deep structural architecture, evolution and dynamics, the short-path, multi-source heating mode, Hot Dry Rock geothermal energy, oil and gas reservoir, Gonghe Basin

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