地学前缘 ›› 2023, Vol. 30 ›› Issue (4): 65-75.DOI: 10.13745/j.esf.sf.2022.10.12

• 深层海相碳酸盐岩油气地质 • 上一篇    下一篇

塔河油田奥陶系古岩溶洞穴充填物时代鉴别特征及其储集意义

陈轩1(), 刘王涵1, 鲍典2, 张利萍1,*(), 陈立雄3, 杨敏2, 张娟2, 李英菊4, 李广业5, 加玉锋6   

  1. 1.长江大学 地球科学学院, 湖北 武汉 430100
    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
    3.中国石油集团测井有限公司 天津分公司, 天津 300280
    4.辽河油田 勘探开发研究院, 辽宁 盘锦 124010
    5.新疆油田公司 采油二厂, 新疆 克拉玛依 834000
    6.新疆油田重油公司 油田地质研究所, 新疆 克拉玛依 834000
  • 收稿日期:2022-05-30 修回日期:2023-02-02 出版日期:2023-07-25 发布日期:2023-07-07
  • 通讯作者: *张利萍(1982—),女,博士,讲师,主要从事储层地质学研究工作。E⁃mail: 83728599@qq.com
  • 作者简介:陈 轩(1983—),男,博士,教授,主要从事沉积学、储层地质学研究工作。E-mail: chenxuanwolf@163.com
  • 基金资助:
    国家自然科学基金项目(41302119)

Ordovician palaeokarst caves in the Tahe oilfield: Burial age of cave fills and its implication for hydrocarbon reservoirs

CHEN Xuan1(), LIU Wanghan1, BAO Dian2, ZHANG Liping1,*(), CHEN Lixiong3, YANG Min2, ZHANG Juan2, LI Yingju4, LI Guangye5, JIA Yufeng6   

  1. 1. School of Geosciences, Yangtze University, Wuhan 430100, China
    2. Northwest Oilfield, Sinopec, ürümqi 830011, China
    3. Tianjin Branch, CNPC Logging Co., Ltd, Tianjin 300280, China
    4. Research Institute of Exploration and Development, Liaohe Oilfield, CNPC, Panjin 124010, China
    5. No.2 Oil Production Plant of Xinjiang OilField Company, Karamay 834000, China
    6. Heavy Oil plant of Xinjiang OilField Company, Karamay 834000, China
  • Received:2022-05-30 Revised:2023-02-02 Online:2023-07-25 Published:2023-07-07

摘要:

洞穴充填物的充填时代分析能够帮助认识洞穴的形成过程、充填结构序列和储集空间发育规律。塔河油田奥陶系岩溶洞穴受到物理充填作用的显著影响,其充填物的时代鉴别特征及其对储集空间发育的影响缺乏系统的分析。基于塔河油田奥陶系地质背景、岩心、测井、测年及产能资料的分析,认为:(1)灰绿色层理构造钙质砂岩和泥质粉砂岩为搬运充填成因,与裂缝共生的灰绿色泥质粉砂岩为渗流充填成因,它们的充填时代为海西早期,杂色砾岩的砾石成分复杂,磨圆分选较好,颗粒支撑,也为搬运充填成因,但充填时代为加里东晚期;(2)角砾岩的角砾成分一致,磨圆分选差且被灰绿色渗流泥充填,为海西早期洞穴掩埋时垮塌充填的结果,无渗流泥充填的角砾岩,裂纹化且多含方解石或沥青,多发育在洞穴顶部,为深埋藏阶段垮塌作用的结果;(3)岩溶洞穴缝洞储集体控制因素十分复杂,洞穴掩埋期的搬运、渗流与垮塌作用多产生泥质充填,储集性差;深埋藏期垮塌作用,产生次级裂缝且无泥质充填,储集性好,洞穴顶部及上部为有利储层发育位置。本研究为岩溶洞穴形成过程和油气藏高效开发提供有价值的参考。

关键词: 古岩溶洞穴, 缝洞储集体, 充填时代, 垮塌充填, 奥陶系, 塔河油田

Abstract:

The burial age of cave fills can provide valuable insights into the formation of ancient caves and the cave filling order and cave reservoir development. The Ordovician palaeokarst caves in the Tahe oilfield are significantly impacted by cave filling, but the burial age of cave fills and its implication for the hydrocarbon reservoir development in the oil field have not been systematically analyzed. Here we present findings on the cave deposits based on analyses of the geologic setting of the oil field as well as core, well-logging, burial history and productivity data. We found the layered, gray-green calcareous sandstone and argillaceous siltstone were deposited via transport filling in the Early Hercynian and fracture-associated, gray-green argillaceous siltstones via seepage filling in the same era; whilst well-rounded/sorted, multicolor conglomerate fills, with complex rock composition and sandy matrix, were deposited in the Late Caledonian by transport filling. Meanwhile, poorly-sorted collapse breccias, chemically homogeneous, mixed with grey-green mudstone via seepage filling, were deposited in the Early Hercynian during early burial; whilst fractured, calcite/oil-bearing collapse breccias, mainly on cave roof, without seepage filling, were deposited in the late burial stage. The reservoir controlling factors of fracture/cavity reservoirs of karst caves were very complex, where cave fills deposited in the early burial stage via transport, seepage and collapse filling were mostly mudstones, with poor reservoir quality; whereas secondary fractures formed during late burial from collapse settlement without mud fill greatly improved reservoir quality, and the upper/top parts of karst caves were favorable for reservoir development. This research provided a valuable reference for the understanding of karst cave formation and exploration of high-quality hydrocarbon reservoirs.

Key words: palaeo-karst caves, fracture-cave reservoirs, filling ages, collapsed fillings, Ordovician, Tahe oilfield

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