石油与天然气地质 ›› 2016, Vol. 37 ›› Issue (1): 117-124.doi: 10.11743/ogg20160116

• 油气开发 • 上一篇    下一篇

致密油气藏储层应力敏感各向异性及其微观机制——以鄂尔多斯盆地安塞油田长6油层为例

张志强, 师永民, 李鹤   

  1. 北京大学地球与空间科学学院, 北京 100871
  • 收稿日期:2015-06-03 修回日期:2016-01-04 出版日期:2016-02-08 发布日期:2016-03-02
  • 通讯作者: 师永民(1966-),男,研究员,低渗油田开发和储层地质。E-mail:sym@pku.edu.cn。 E-mail:sym@pku.edu.cn
  • 作者简介:张志强(1990-),男,硕士,低渗油田开发地质。E-mail:zhiqiangzhang@pku.edu.cn。
  • 基金资助:
    国家重点基础研究发展计划(973计划)项目(2009CB219302)。

Stress sensitivity anisotropy and its microscopic mechanism of tight oil and gas reservoirs: A case from the Chang-6 reservoir in Ansai oilfield of Ordos Basin

Zhang Zhiqiang, Shi Yongmin, Li He   

  1. School of Earth and Space Science, Peking University, Beijing 100871, China
  • Received:2015-06-03 Revised:2016-01-04 Online:2016-02-08 Published:2016-03-02

摘要: 中国陆相致密储层应力敏感各向异性研究对低渗透油气藏开发过程中储层伤害评价具有重要作用。鉴于注水开发过程中的实际问题,选取鄂尔多斯盆地安塞油田长6油层3块典型岩样,分别从水平XY及垂直Z方向钻取小岩心柱,并依次恢复至地层条件下变化围压测定渗透率,并结合铸体薄片、扫描电镜及XRD等实验,对致密油气藏储层渗透率应力敏感各向异性及其微观机制进行分析。研究结果表明:不同岩样的应力敏感性存在差异,且同一岩样不同方向的应力敏感性也存在差异,应力敏感性指数由强到弱分别为细粒岩屑长石砂岩、长石岩屑质石英粉砂岩和中细粒岩屑长石砂岩,各向异性系数由强到弱分别为长石岩屑质石英粉砂岩、中细粒岩屑长石砂岩和细粒岩屑长石砂岩。通过微观实验可知,不同类型储层的矿物成分、排列方式及孔隙结构特征差异大,是造成储层应力敏感各向异性的关键因素。因此认为,致密油气藏不同类型储层应力敏感及各向异性存在较大差异,而储层微观非均质性特征是应力敏感及各向异性的主要影响因素。这一结论对鄂尔多斯盆地陆相致密非均质性储层的高效开发具有重要意义。

关键词: 应力敏感性, 各向异性, 微观非均质性, 油田开发, 致密油气藏, 鄂尔多斯盆地

Abstract: Study on stress sensitivity anisotropy of continental tight reservoirs in China plays an important role in evaluation of reservoir damage during the exploitation of low permeability oilfield.In view of the practical problems,the X,Y and Z columns from three inter-perpendicular orientation of three typical samples from Chang-6 reservoir in Ansai oilfield of Ordos Basin are used to test permeability by changing confining pressure under the in-situ condition and study the relationship between permeability and effective stress.In addition,microscopic mechanism and anisotropy of stress sensitivity in tight oil and gas reservoirs are analyzed through integrating various data including casting thin sections,scanning electron microscopy and XRD,etc.The results demonstrate that stress sensitivities of different rock samples are different and stress sensitivities of the same rock sample are also quite different in different directions.The ranking of stress sensitivity index from strong to weak is fine-grained lithic feldspathic sandstone,feldspar lithic quartz siltstone and medium to fine-grained lithic feldspathic sandstone,and the ranking of anisotropy coefficient from strong to weak is feldspar lithic quartz siltstone,medium to fine-grained lithic feldspathic sandstone and fine-grained lithic feldspathic sandstone.Microscopic experiments indicate that mineral composition,the arrangement and pore structure characteristics of different types of reservoir are key factors to cause reservoir stress sensitivity anisotropy.Therefore,stress sensitivity anisotropies are quite different in different types of tight reservoirs,and the microscopic heterogeneity characteristics of reservoirs are the major factors influencing stress sensitivity and anisotropy.This understanding is of great significance to highly-efficient exploitation of the continental heterogeneous tight reservoirs in Ordos Basin.

Key words: stress sensitivity, permeability anisotropy, microscopic heterogeneity, oilfield development, tight Oil & Gas reservoir, Ordos Basin

中图分类号: