石油与天然气地质 ›› 2016, Vol. 37 ›› Issue (1): 62-71.doi: 10.11743/ogg20160109

• 油气地质 • 上一篇    下一篇

致密储层脆性特征及对天然裂缝的控制作用——以鄂尔多斯盆地陇东地区长7致密储层为例

赵向原1,2, 曾联波2, 祖克威3, 胡向阳1, 焦军4, 朱利锋5, 史今雄2   

  1. 1. 中国石化石油勘探开发研究院, 北京 100083;
    2. 中国石油大学(北京)地球科学学院, 北京 102249;
    3. 中国石化中原油田分公司勘探开发科学研究院, 河南郑州 450018;
    4. 中国石油长庆油田分公司勘探开发研究院, 陕西西安 710018;
    5. 山西省地质调查院, 山西太原 030006
  • 收稿日期:2015-08-28 修回日期:2015-12-20 出版日期:2016-02-08 发布日期:2016-03-02
  • 通讯作者: 曾联波(1967-),男,博士、博士生导师,储层裂缝形成与分布预测。E-mail:lbzeng@sina.com。 E-mail:lbzeng@sina.com
  • 作者简介:赵向原(1983-),男,博士,低渗透油气田开发地质。E-mail:auxus@sina.com。
  • 基金资助:
    国家科技重大专项(2011ZX05013-004)。

Brittleness characteristics and its control on natural fractures in tight reservoirs: A case study from Chang 7 tight reservoir in Longdong area of the Ordos Basin

Zhao Xiangyuan1,2, Zeng Lianbo2, Zu Kewei3, Hu Xiangyang1, Jiao Jun4, Zhu Lifeng5, Shi Jinxiong2   

  1. 1. Petroleum Exploration & Production Research Institute, SINOPEC, Beijing 100083, China;
    2. College of Geosciences, China University of Petroleum, Beijing 102249, China;
    3. Exploration and Development Research Institute, Zhongyuan Oilfield Company, SINOPEC, Zhengzhou, Henan 450018, China;
    4. Exploration and Development Research Institute, Changqing Oilfield Company, PetroChina, Xi'an, Shaanxi 710018, China;
    5. Shanxi Geological Survey, Taiyuan, Shanxi 030006, China
  • Received:2015-08-28 Revised:2015-12-20 Online:2016-02-08 Published:2016-03-02

摘要: 研究致密储层脆性特征及对天然裂缝的控制作用对天然裂缝定量预测具有重要意义。在总结了国内外脆性测试的20余种方法的基础上,重点论述了非常规油气中脆性评价方法的发展和应用情况,并以鄂尔多斯盆地陇东地区长7致密储层为例,在天然裂缝发育特征的基础上,对储层脆性特征进行评价,并探讨储层脆性对裂缝的控制作用。研究表明,陇东地区长7储层发育多组高角度构造裂缝,这些裂缝广泛分布在不同的岩性中。储层中不同岩性脆性特征差异性较大,其中砂岩脆性最大,含泥质砂岩次之,泥岩脆性最小,表现出随着泥质含量增加,脆性指数逐渐减小的特征。在特定的古构造应力背景下,储层脆性控制了天然裂缝的发育特征及发育程度。当岩层脆性指数大于某一值时更易发育高角度裂缝,而低于这一值时更易发育中-低角度裂缝。脆性也控制了储层自身的破裂能力。随着岩层脆性指数增大,在构造应力作用下岩层越易发生破裂导致裂缝发育程度较高;而脆性指数越低,岩层越易发生形变而非破裂,裂缝发育程度较弱或基本不发育。

关键词: 脆性特征, 天然裂缝, 致密储层, 延长组, 鄂尔多斯盆地

Abstract: Study of brittleness of tight reservoir and its effect on natural fractures is of great significance to quantitative prediction of natural fractures in tight reservoirs.This paper summarized more than 20 brittleness testing methods,focusing on the development and application of brittleness evaluation methods for unconventional oil and gas reservoirs.Moreover,it also evaluated the brittleness characteristics of tight reservoir and its effect on natural fractures in the Chang 7 tight reservoir in Longdong area of Ordos Basin.The results show that several groups of high angle structural fractures are developed widely in intervals of various lighologies in the Chang 7 reservoir in Longdong area.Sandstones show the highest brittleness,followed by shaly sandstones,and mudstones has the lowest brittleness.The brittleness decreases with the increase of shale content.On the specific paleo-structure stress background,rock brittleness controls the development characteristics and development degree of natural fractures.There is a brittleness threshold,above which high angle fractures are more likely to develop,while below which it is likely to develop low angle fractures.Brittleness also controls rock fracturing ability.When brittleness index is large,rock is easier to fracture under the structure stress,resulting in more fractures.In contrast,when it is low,rock deforms instead of fracturing,thus fractures are poorly developed and even not developed.

Key words: brittleness characteristics, natural fracture, tight reservoir, Yanchang Formation, Ordos Basin

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