西南石油大学学报(自然科学版) ›› 2017, Vol. 39 ›› Issue (6): 63-68.DOI: 10.11885/j.issn.1674-5086.2016.07.09.05

• 地质勘探 • 上一篇    下一篇

地层孔隙压力变化对井壁稳定性的影响研究

李伟1, 梁利喜2, 刘向君2, 王涛3   

  1. 1. 陕西延长石油(集团)有限责任公司研究院, 陕西 西安 710065;
    2. "油气藏地质及开发工程"国家重点实验室 西南石油大学, 四川成气藏地质及开发, 四川 成都 610500;
    3. 新疆克拉玛依红山油田有限责任公司, 新疆 克拉玛依 834000
  • 收稿日期:2016-07-09 出版日期:2017-12-01 发布日期:2017-12-01
  • 通讯作者: 梁利喜,E-mail:liangzby@163.com
  • 作者简介:李伟,1970年生,男,汉族,陕西西安人,高级工程师,主要从事钻井、固井技术研究。E-mail:liweixian@sohu.com;梁利喜,1976年生,男,汉族,河南新乡人,讲师,博士/后,主要从事井眼稳定技术、岩石物理与岩石力学、石油工程测井的研究。E-mail:liangzby@163.com;刘向君,1969年生,女,四川资中人,教授,博士生导师,博士,主要从事要从事岩石力学及岩石物理、井壁稳定和防砂完井、测井交叉方面的教学与研究工作。E-mail:liuxiangjunswpi@163.com;王涛,1972年生,男,汉族,甘肃玉门人,工程师,主要从事油气田开发、地面建设及设备管理工作。E-mail:190728351@qq.com
  • 基金资助:
    国家自然科学基金石油化工联合基金重点支持项目(U1262209);国家自然科学基金(51274172);四川省应用基础研究计划(2014JY0092)

Study on the Effects of Changes in Pore Pressure on Wellbore Stability

LI Wei1, LIANG Lixi2, LIU Xiangjun2, WANG Tao3   

  1. 1. Yanchang Petroleum Group Research Institute, Shaanxi Yanchang Petroleum(Group) Corp. Ltd., Xi'an, Shaanxi 710065, China;
    2. State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan 610500, China;
    3. Xinjiang Karamay Hongshan Oilfield Co. Ltd., Karamay, Xinjiang 834000, China
  • Received:2016-07-09 Online:2017-12-01 Published:2017-12-01

摘要: 受长期注采工程作业的影响,地层孔隙压力将发生大幅度波动,从而导致地层的岩石强度、地应力相对开采初期已发生较大变化,且横向分布更为复杂,进而诱发、加剧井壁失稳,井下复杂状况频发。理论与实验相结合研究了孔隙压力变化对砂岩地层岩石强度及地层坍塌压力的影响,结果表明:(1)岩石强度与地层孔隙压力呈负相关,随地层孔隙压力增大,地层岩石强度、弹性模量呈线性递减;(2)地层孔隙压力变化将影响调整井的井壁稳定状态,压裂、注水、注聚等工程作业导致井周地层孔隙压力增大,将加剧井眼失稳;而在一定限度内,油气的压力衰减式开采将降低地层坍塌压力,利于井眼保持稳定。

关键词: 井壁稳定, 孔隙压力, 岩石强度, 坍塌压力

Abstract: Long-term injection/projection operations cause large fluctuations in pore pressure, which in turn cause relatively large changes in rock strength and ground stress in the strata compared to the initial stage of mining. Furthermore, the complexity in the horizontal distribution of pore pressure induces and exacerbates wellbore instability and results in frequent occurrences of complex downhole situations. We carried out a combined theoretical and experimental study to understand the effects of pore pressure changes on the rock strength and stratum collapse pressure of sandstone strata. The results show that:(1) Rock strength is negatively correlated with pore pressure. As pore pressure increases, stratum rock strength and elastic modulus show a linear decrease. (2) Changes in pore pressure affect wellbore stability. Fractures, water injection, and polymer injection operations result in increased pore pressure around the well, which exacerbates wellbore instability. In addition, pressure-attenuated mining of oil and gas within a certain range decreases the stratum collapse pressure, which is beneficial for maintaining wellbore stability.

Key words: wellbore stability, pore pressure, rock strength, collapse pressure

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