西南石油大学学报(自然科学版) ›› 2018, Vol. 40 ›› Issue (3): 1-10.DOI: 10.11885/j.issn.1674-5086.2017.01.24.02

• 地质勘探 •    下一篇

鄂尔多斯盆地西南部长8砂岩致密时间再认识

周晓峰1,2, 李景3, 张建欣4, 李书恒5, 于均民1,2   

  1. 1. 中国石油大学(北京)石油工程教育部重点实验室, 北京 昌平 102249;
    2. 油气资源与工程国家重点实验室, 北京 昌平 102249;
    3. 中国石油玉门油田勘探开发研究院, 甘肃 酒泉 735019;
    4. 西南石油大学地球科学与技术学院, 四川 成都 610500;
    5. 中国石油长庆油田分公司勘探开发研究院, 陕西 西安 710018
  • 收稿日期:2017-01-24 出版日期:2018-06-01 发布日期:2018-06-01
  • 通讯作者: 周晓峰,E-mail:zhouxf@cup.edu.cn
  • 作者简介:周晓峰,1973年生,男,汉族,甘肃甘谷人,讲师,博士,主要从事油气田地质学方面的教学和科研工作。E-mail:zhouxf@cup.edu.cn;李景,1986年生,男,汉族,甘肃酒泉人,工程师,主要从事油田开发综合研究工作。E-mail:ylij@petrochina.com.cn;张建欣,1991年生,男,汉族,甘肃酒泉人,硕士研究生,主要从事油气田开发地质方面的科研工作。E-mail:729411850@qq.com;李书恒,1969年生,男,甘肃宁县人,高级工程师,硕士,主要从事油气田开发方面的科研和生产工作。E-mail:lsh2_cq@petrochina.com.cn;于均民,1974年生,女,汉族,黑龙江桦南人,工程师,博士,主要从事储层地质学研究工作。E-mail:yujm2002@sina.com
  • 基金资助:
    国家科技重大专项(2011ZX05013-006);国家级矿产资源综合利用示范基地项目(国土资厅发[2011]88号文件)

Revisiting the Compaction Time of Chang 8 Sandstones in Southwestern Ordos Basin

ZHOU Xiaofeng1,2, LI Jing3, ZHANG Jianxin4, LI Shuheng5, YU Junmin1,2   

  1. 1. MOE Key Laboratory of Petroleum Engineering, China University of Petroleum, Changping, Beijing 102249, China;
    2. State Key Laboratory of Petroleum Resources and Engineering, Changping, Beijing 102249, China;
    3. Exploration and Development Research Institute of Yumen Oilfield Company, PetroChina, Jiuquan, Gansu 735019, China;
    4. School of Geoscience and Technology, Southwest Petroleum of University, Chengdu, Sichuan 610500, China;
    5. Exploration and Development Research Institute of Changqing Oilfield Company, PetroChina, Xi'an, Shaanxi 710000, China
  • Received:2017-01-24 Online:2018-06-01 Published:2018-06-01

摘要: 鄂尔多斯盆地延长组砂岩的致密时间目前尚无定论,这是由于对方解石胶结物的成因认识不一致造成的。通过铸体薄片和带有能谱仪的扫描电镜技术,对鄂尔多斯盆地西南部长8砂岩中方解石胶结物的成因进行了研究。认为早成岩A期的泥岩压释水为方解石胶结提供物质来源,形成了浸染状均匀分布的I型方解石胶结物和斑块状或星点状散布的Ⅱ0型方解石胶结物; I型方解石胶结的砂岩,流体难以进入而失去水岩反应能力,Ⅱ0型方解石胶结物在中成岩A期经溶解沉淀反应转化为Ⅱ型方解石胶结物;碳氧同位素和流体包裹体资料不能作为研究方解石胶结物成因的主要依据,这些资料的解释必须服从于岩石显微结构特征。鉴于此,鄂尔多斯盆地西南部长8砂岩致密时间为早成岩A期,其与成藏时期的配置关系为先致密后成藏。

关键词: 致密时间, 方解石胶结物, 显微结构, 先致密后成藏, 延长组, 鄂尔多斯盆地

Abstract: Owing to disagreements in the understanding of calcite cement formation, the compaction time of sandstones of the Yanchang Formation in Ordos Basin has not yet been determined. Employing scanning electron microscopy (SEM) with energy spectrometry and casted rock thin sections, the origin of calcite cement in Chang 8 sandstones in southwestern Ordos Basin was investigated. The results show that water released from mudstone compaction during phase A of the early diagenetic stage induced calcite cementation, forming type I calcite cement with evenly distributed dissemination structures or type Ⅱ0 with patchy or scattered dissemination structures. Fluids cannot easily penetrate sandstones derived from type I calcite cementation, and thus water-rock reactions cannot take place. Type Ⅱ0 calcite cement is transformed into type Ⅱ via dissolution-precipitation during phase A of the mid-diagenetic stage. Carbon and oxygen isotopes and fluid inclusion data cannot be used as the main reference for studying calcite cement formation because their interpretation must follow rock microstructure characteristics. In view of the above, the compaction time of Chang 8 sandstones in southwestern Ordos Basin was determined to be phase A of the early diagenetic stage, and its relationship with reservoir formation is "compaction followed by accumulation."

Key words: compaction time, calcite cement, microstructure, compaction followed by accumulation, Yanchang Formation, Ordos Basin

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