油气藏评价与开发 ›› 2019, Vol. 9 ›› Issue (5): 54-62.

• 方法理论 • 上一篇    下一篇

水—岩作用对富有机质页岩应力敏感性的影响——以渝东南地区龙马溪组页岩为例

康毅力1,白佳佳1,李相臣1,陈明君1,游利军1,李鑫磊1,李清2,房大志2   

  1. 1. 西南石油大学油气藏地质及开发工程国家重点实验室,四川 成都 610500
    2. 中国石化华东油气分公司勘探开发研究院,江苏 南京 210000
  • 收稿日期:2019-04-20 出版日期:2019-10-26 发布日期:2019-10-26
  • 作者简介:康毅力(1964 —),男,教授,博士生导师,从事储层保护理论与技术、非常规天然气、油气田开发地质研究。通讯地址:四川省成都市新都区新都大道8号,邮政编码:610500。E-mail: cwctkyl@163.com
  • 基金资助:
    “十三五”国家科技重大专项“彭水地区常压页岩气勘探开发示范工程”(2016ZX05061);国家自然科学基金“富有机质页岩氧化致裂增渗加速气体传输机理研究”(51674209);非常规油气层保护四川省青年科技创新团队项目“水力压裂页岩气井热处理解除损害及强化产能研究”(2016TD0016)

Influence of water-rock interaction on stress sensitivity of organic-rich shales: A case study from Longmaxi formation in the southeast area of Chongqing

KANG Yili1,BAI Jiajia1,LI Xiangchen1,CHEN Mingjun1,YOU Lijun1,LI Xinlei1,LI Qing2,FANG Dazhi2   

  1. 1. State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan 610500, China
    2. Research Institute of Exploration and Development, Sinopec East China Oil and Gas Company, Nanjing, Jiangsu 210000, China
  • Received:2019-04-20 Online:2019-10-26 Published:2019-10-26

摘要:

页岩气的产出是跨越多种尺度,历经多种传质方式的复杂过程。每一个路径的应力敏感性都会对页岩气的传质过程产生重要影响。尤其是当巨量压裂液滞留在页岩储层中,水—岩作用必然会对页岩应力敏感性产生影响。以渝东南地区龙马溪组页岩为研究对象,开展了水—岩作用前后页岩应力敏感性评价实验,表征了应力敏感实验前后裂缝面性质变化特征,分析了水—岩作用对裂缝面的作用机理。页岩初始缝宽越宽,应力敏感性越强。页岩发生水—岩作用后其应力敏感程度从高到低依次为:碱敏>矿化度降低的盐敏>水敏。矿化度降低的盐敏和水敏过程中,黏土矿物水化膨胀,并发生了微粒运移,裂缝表面更加光滑;而碱敏过程流体不仅与裂缝表面发生了水化作用,而且发生了碱液侵蚀,加剧了页岩应力敏感程度。含支撑剂的裂缝页岩应力敏感程度减弱,支撑剂的嵌入和破碎是产生应力敏感性的主要原因,支撑剂优选和合理铺置是降低应力敏感程度的关键。

关键词: 孔隙结构, 裂缝面性质, 水—岩作用;, 应力敏感性, 页岩

Abstract:

The production of shale gas is a complex and multiscale process that spans a variety of scales and goes through a variety of mass transfer mode. The stress sensitivity of each path has an important influence on the mass transfer of shale gas. Especially when a large amount of fracturing fluid retained in shale reservoir, water-rock interactions will inevitably affect shale stress sensitivity. Taking Longmaxi Formation shale in the southeast area of Chongqing as the research object, stress sensitivity experiments of shale before and after water-rock interactions are carried out, which characterize the change characteristics of fracture surface properties before and after stress sensitivity experiments, and analyze the action mechanisms of water-rock interaction on the fracture surface. It is found that, the stress sensitivity of fractured shale containing proppants is weak, and the existence of proppants reduce the stress sensitivity of shale. The wider the crack width is, the stronger the stress sensitivity will be. The stress sensitivity of shale after water-rock interaction is from high to low in the following order: alkali sensitivity>salt sensitivity with reduced salinity>water sensitivity. In the process of salt sensitivity and water sensitivity with reduced salinity, clay minerals hydrate and expand, and particles migrate, resulting in smoother fracture surfaces. However, the alkali-sensitive process, the fluid not only hydrates with the fracture surface, but also causes the alkali erosion, which strengthens the shale stress sensitivity. The stress sensitivity of fracture shale containing proppant is weakened, and the embedding and crushing of propelling agent is the main cause of stress sensitivity. The optimal selection and reasonable laying of propelling agent is the key to reduce the stress sensitivity.

Key words: pore structure, nature of fracture surface, water-rock interaction, stress sensitivity, shale

中图分类号: 

  • TE312