东北石油大学学报2025，Vol.49Issue(2)：97-106,10.DOI:10.3969/j.issn.2095-4107.2025.02.008
钻井液驱替下古龙页岩力学特性及弱化规律
Mechanical properties and weakening law of Gulong shale under drilling fluid displacement
摘要
Abstract
In the process of shale oil drilling,due to the redistribution of ground stress around the well-bore and the intensification of hydration,wellbore instability becomes an urgent problem to be solved.The microphysical and macroscopic mechanical properties of the Gulong shale oil layer are studied.The results show that the average pore diameter of the bedding seam is 160.94 μm,and the average pore di-ameter of the sandy strip is 1.50 μm.The shale has significant anisotropic permeability,in which the permeability parallel to the bedding direction is about twice that of the vertical bedding direction.The upper and lower limit angles of shale bedding plane failure are defined,and a chart showing the distribu-tion of shale strength with the dip angle of weak plane under different confining pressures is made.The failure model considering shale oil bedding plane is established and verified with the experimental re-sults.The average error is about 8.25％.In the vertical bedding direction,the triaxial compressive strength of rock after displacement by water-based drilling fluid,alcohol-based drilling fluid and oil-based drilling fluid decreased by 20.31％,17.67％ and 13.69％,respectively.In the horizontal bedding direction,the rock triaxial compressive strength of water-based drilling fluid,alcohol-based drilling fluid and oil-based drilling fluid after displacement decreased by 36.15％,31.78％ and 22.44％,respectively,and the failure criterion of shale after weakening was modified.Based on the field data,this paper sum-marizes the current progress in the study of wellbore instability in Gulong shale,and determines the safe drilling fluid density window of Qingshankou Formation:1.71-1.73 g/cm3.The drilling fluid with this parameter can form an effective mechanical support to the wellbore,help to effectively prevent forma-tion spalling,and provide a clear adjustment direction for the optimal ratio of main and auxiliary emulsi-fier.The research results have certain guiding significance for the safe drilling of Gulong shale oil drill-ing project.关键词
古龙页岩油/井壁失稳/钻井液/各向异性/破坏模型/力学特性/弱化规律Key words
Gulong shale oil/wellbore instability/drilling fluid/anisotropy/failure model/mechanical properties/weakening law分类
能源科技引用本文复制引用
索彧,李芬芬,何文渊,付晓飞,潘哲君,齐悦,董牧宇..钻井液驱替下古龙页岩力学特性及弱化规律[J].东北石油大学学报,2025,49(2):97-106,10.基金项目
新时代龙江优秀硕士、博士论文资助项目(LJYXL2022-002) （LJYXL2022-002）
黑龙江省博士后面上基金资助项目(LBH-Z22044) （LBH-Z22044）
黑龙江省博士后特别资助基金项目(LBH-TZ2301) （LBH-TZ2301）
黑龙江省"揭榜挂帅"科技攻关项目(DQYT-2022-JS-758) （DQYT-2022-JS-758）
