西南石油大学学报(自然科学版) ›› 2020, Vol. 42 ›› Issue (5): 135-144.DOI: 10.11885/j.issn.1674-5086.2019.06.14.01

• 石油与天然气工程 • 上一篇    下一篇

考虑岩石弹塑性变形的井周应力场计算模型研究

李小刚1, 李昀昀2, 胡秋萍3, 张翔3, 易良平1   

  1. 1. 油气藏地质及开发工程国家重点实验室·西南石油大学, 四川 成都 610500;
    2. 中海油能源发展股份有限公司工程技术分公司非常规院, 天津 滨海新区 300452;
    3. 中联煤层气有限责任公司晋城分公司, 山西 晋城 048000
  • 收稿日期:2019-06-14 出版日期:2020-10-10 发布日期:2020-10-10
  • 通讯作者: 易良平,E-mail:ylpfrac@163.com
  • 作者简介:李小刚,1981年生,男,汉族,四川仁寿人,教授,博士,主要从事油气藏增产改造的教学与科研工作。E-mail:swpuadam@126.com;李昀昀,1973年生,女,汉族,四川成都人,工程师,主要从事油气田增产措施工艺技术研究。E-mail:liyy15@cnooc.com.cn;胡秋萍,1985年生,女,汉族,湖北黄冈人,工程师,主要从事煤层气开发与生产的研究及管理工作。E-mail:huqp@cnooc.com.cn;张翔,1990年生,男,汉族,山西晋城人,工程师,主要从事煤层气排采研究。E-mail:zhangxiang15@cnooc.com.cn;易良平,1991年生,男,汉族,四川泸州人,讲师,博士,主要从事油气藏增产改造的教学与科研工作。E-mail:ylpfrac@163.com
  • 基金资助:
    国家科技重大专项(2017ZX05064)

A Study on Calculation Model of Stress Field Around Wells Considering Rock Elastic-plastic Deformation

LI Xiaogang1, LI Yunyun2, HU Qiuping3, ZHANG Xiang3, YI Liangping1   

  1. 1. State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan 610500, China;
    2. CNOOC EnerTech-Drilling & Production Co., Binhai New Area, Tianjin 300452, China;
    3. Jincheng Branch, China United Coalbed Methane Co. Ltd., Jincheng, Shanxi 048000, China
  • Received:2019-06-14 Online:2020-10-10 Published:2020-10-10

摘要: 针对煤岩、页岩等岩石具有弹塑性这一特性,考虑岩石非线性硬化与软化变形,并耦合工作液渗滤作用,沿井筒径向方向将地层分为塑性软化、塑性硬化和弹性区,根据弹性区与塑性区交界处应力连续的特点,建立了耦合工作液渗滤和岩石非线性硬化与软化变形的井壁应力场模型。分析表明,塑性区大小与井眼流体压力、泊松比和地层初始孔隙流体压力呈正相关关系,与岩石强度呈负相关关系。与弹性状态相比,岩石塑性变形降低了井眼应力集中效应,岩石塑性变形对井周径向应力影响较小,但会使井周周向应力增加。

关键词: 煤岩, 页岩, 弹塑性, 非线性本构, 井周应力

Abstract: Aiming at the elastic-plastic characteristics of coal, shale and other rocks, a calculation method for stress field of elastic-plastic formation is established, which divide the formation into the plastic softening, the plastic hardening and the elastic zone along the radial direction. In this new model the nonlinear hardening and softening deformation of rock and the percolation effect of the working fluid are considered. The analysis shows that the plastic zone range is positively correlated with the borehole fluid pressure, Poisson's ratio and the initial pore fluid pressure, and is inversely related to the strength of the rock. Compared with the elastic state, the plastic deformation of rock decreases the stress concentration effect, and the plastic deformation of the rock has a little influence on the radial stress of the formation while it can increase the circumferential stress of the formation.

Key words: coal, shale, elastic-plastic, nonlinear constitutive equation, stress field around wellbore

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