西南石油大学学报(自然科学版)

• 石油与天然气工程 • 上一篇    下一篇

基于霍克–布朗准则评价页岩气井井壁稳定性

梁利喜,刘向君   

  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
  • 出版日期:2014-10-01 发布日期:2014-10-01
  • 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)。

Research on Wellbore Stability of Shale Gas Based on
Hoek-Brown Criterion

Liang Lixi, Liu Xiangjun   

  1. State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Southwest Petroleum University,Chengdu,Sichuan 610500,China
  • Online:2014-10-01 Published:2014-10-01

摘要:

井壁稳定是实现页岩气水平井低成本、安全、高效钻井的核心技术之一,科学的井壁稳定性评价理论及方法
是保障井壁稳定的前提与基础。页岩储层力学性能取决于结构面的发育程度、几何形态、组合特征及其力学性质等因
素;受结构面产状及其力学参数获取困难的制约,目前普遍采用的弱面理论与莫尔–库仑准则相结合的井壁稳定性评
价方法,仅局限于理论研究,尚未得到有效工程应用。鉴于此,开展了基于霍克–布朗强度理论的页岩地层井壁稳定性
评价研究。通过构建含有不同裂隙的数值模型,进行不同围压下的三轴压缩数值仿真模拟,分析了参数mb、S 与岩体
结构的关系,建立了基于结构面发育指数J 的mb、S 量化方法。分析表明:基于该理论所得地层坍塌压力与实钻井垮
塌失稳导致的井眼不规则具有较好的一致性,评价结果可靠,为页岩气井的井壁稳定性科学评价提供了新方法。

关键词: 页岩, 井壁稳定, Hoek&ndash, Brown, 结构面, 岩石强度

Abstract:

The wellbore stability is one of the key technologies in order to achieve rule horizontal wellbore in shale with low cost.
Due to the occurrence and the difficulty in obtaining mechanical parameters of the underground structural planes,the evaluation
method of borehole stability by weak surface theory and Mohr-Coulomb criterion has not yet been applied in engineering,and
was only studied in theory. In this paper,wellbore stability has been evaluated by using Hoek - Brown criterion. The core
numerical model with different fractures has been created,and the tri-axial compression test with different confine pressures
has been carried out by means of the numerical simulation. Relationship between the parameters mb,S and rock mass structure
has been analyzed using the result of the numerical simulation. And the method to determine the parameters mb,S has been
established with fracture development index. The analysis of engineering example shows that collapse pressure obtained with
the theory are consistent with the actual drilling performance in shale formation and a new method for evaluating borehole
stability of shale gas wells has been provided.

Key words: shale, wellbore stability, Hoek-Brown criterion, structural planes, rock strength