Acta Petrolei Sinica ›› 2016, Vol. 37 ›› Issue (4): 439-453.DOI: 10.7623/syxb201604003

• Petroleum Exploration • Previous Articles     Next Articles

Cambrian hydrothermal action in Gucheng area, Tarim Basin and its influences on reservoir development

Wang Kun1, Hu Suyun1, Hu Zaiyuan2, Liu Wei1, Huang Qingyu1, Shi Shuyuan1, Ma Kui1, Li Mei3   

  1. 1. PetroChina Research Institute of Petroleum Exploration & Development, Beijing 100083, China;
    2. Northwest Branch, PetroChina Research Institute of Petroleum Exploration & Development, Gansu Lanzhou 730020, China;
    3. China University of Petroleum, Beijing 102249, China
  • Received:2015-10-10 Revised:2016-02-18 Online:2016-04-25 Published:2016-05-06

塔里木盆地古城地区寒武系热液作用及其对储层发育的影响

王坤1, 胡素云1, 胡再元2, 刘伟1, 黄擎宇1, 石书缘1, 马奎1, 李梅3   

  1. 1. 中国石油勘探开发研究院 北京 100083;
    2. 中国石油勘探开发研究院西北分院 甘肃兰州 730020;
    3. 中国石油大学 北京 102249
  • 通讯作者: 胡素云,男,1963年10月生,1986年获江汉石油学院学士学位,2008年获中国石油大学(北京)地质资源与地质工程专业博士学位,现为中国石油勘探开发研究院总地质师、教授级高级工程师,主要从事石油地质综合研究工作。Email:husy@petrochina.com.cn
  • 作者简介:王坤,男,1985年1月生,2008年获中国矿业大学学士学位,2011年获中国石油大学(北京)硕士学位,现为中国石油勘探开发研究院博士研究生,主要从事碳酸盐岩沉积与储集层研究。Email:wangkuntoby@163.com
  • 基金资助:

    国家重大科技专项(2011ZX05004-001)资助。

Abstract:

Hydrothermal activities are widespread in Tarim Basin. Ordovician hydrocarbon explorations prove that reservoirs can be well improved by hydrotherm but the influences of hydrothermal actives on Cambrian reservoirs have been less studied. The Cambrian core observations in Gucheng area showed an obvious brecciation phenomenon with the development of saddle dolomite and hydrothermal minerals, suggesting that regional reservoirs were intensely transformed by hydrothermal fluid. Through the analyses on trace elements, carbon and oxygen isotopes, strontium isotope and rare earth elements in combination with fluid inclusion thermometry, the temperature, composition and origin of hydrothermal fluid were deduced systematically. Two stages of hydrothermal fluid occurred in Gucheng area, i.e., medium-temperature Cambrian brine and high-temperature intermediate-acid magmatic fluid. According to the burial history, thermal history and tectonic setting analysis, both stages of hydrothermal fluid were further confirmed as typical hydrotherm. The stratigraphic brine was sourced from Manjiaer Depression, and the overpressure caused by hydrocarbon generation was the driving force for upward hydrothermal flow. The activity peak occurred in Devonian with a large scale. The magmatic fluid was sourced from Permian magmatism with a small scale. The rift-tension tectonic setting and the development of strike-slip faults were the reasons for magmatic fluid upwelling. Based on the analysis on reservoir characteristics, it is considered that the stratigraphic brine contained many acidic materials with high water-rock ratio and strong dissolution capacity. The brecciation phenomenon caused by magmatic fluid did not exert a significant improvement on reservoirs, but presented strong cementation, unbeneficial to reservoir development. The scale of strike-slip faults had significant influences on the reservoir improvement by hydrothermal fluid. Medium distance from strike-slip fault or small scale of strike-slip fault was most favorable for improving reservoirs by hydrothermal fluid.

Key words: hydrothermal activities, petrologic characteristics, geochemical characteristics, hydrothermal dissolution, hydrothermal cementation

摘要:

塔里木盆地热液活动普遍,奥陶系油气勘探证实热液对储层有良好的改造作用,但热液活动对寒武系储层的影响研究相对较少。古城地区寒武系岩心观察显示角砾化现象明显,且发育鞍型白云石及热液矿物,表明其受热液改造强烈。通过微量元素、碳氧同位素、锶同位素、稀土元素分析,并结合流体包裹体分析对热液流体的温度、成分、来源进行了系统的分析。本区存在两期热液活动,分别为中等温度的寒武系地层卤水和二叠系高温中酸性岩浆水。通过该区埋藏史、热史及构造背景分析,进一步落实了两期热流体为典型热液。地层卤水来自于满加尔凹陷区,生烃作用导致的超压是热液流动的动力,活动高峰期为泥盆纪,规模较大;岩浆水来自于二叠纪火山作用,规模较小,裂谷拉张的构造背景和走滑断裂的发育是导致岩浆水上涌的原因。通过储层特征的分析,认为地层卤水含有较多的酸性物质,水/岩比例较高,具有较强的溶蚀能力;岩浆水导致的角砾化对储层改造不明显,整体表现出较强的胶结作用,对储层发育不利。走滑断裂带的规模对热液改造的影响明显,与走滑断裂带距离中等或走滑断裂带规模不大时,最利于热液流体对储层的改造。

关键词: 热液活动, 岩石学特征, 地球化学特征, 热液溶蚀, 热液胶结

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