辽宁石油化工大学学报2025，Vol.45Issue(4)：36-46,11.DOI:10.12422/j.issn.1672-6952.2025.04.005
热-流-固-化耦合下裂缝性泥页岩地层井壁失稳特征分析
Analysis of Wellbore Instability Characteristics of Fractured Shale Formation under Thermal-Hydraulic-Mechanical-Chemical Coupling
摘要
Abstract
Wellbore instability is easy to occur when drilling fractured shale formation.Based on mechanical experiments,this paper investigated the weakening law of mechanical properties of shale soaked in drilling fluid.Considering the influence of stress-pressure-temperature-solute concentration disturbance and natural fractures,a multi-field coupled thermal-hydraulic-mechanical-chemical wellbore stability analysis model of fractured shale formation was established.Based on the characteristics of wellbore instability,the window chart of safe drilling density in fractured shale formation with different rock strength parameters is established.The results show that with the increase of drilling fluid soaking time,the strength parameters and elastic parameters of shale deteriorate exponentially.Considering the non-uniform distribution of physical fields around the well after the development of natural fractures,the stress concentration at the crack tip leads to the collapse and tensile failure zone toward it.Increase of horizontal in-situ stress difference and fluid pressure difference will enlarge the tensile and collapse failure zone,and the increase of solute concentration difference will help reduce the failure risk.Increasing drilling fluid temperature has little effect on collapse failure,but it can significantly reduce the risk of tensile failure.The investigation can provide guiding suggestions for safe drilling design in fractured shale formation.关键词
裂缝性地层/泥页岩/井壁失稳/岩石强度弱化/多场耦合Key words
Fractured formation/Shale/Wellbore instability/Weakening of rock strength/Multi-field coupling分类
能源科技引用本文复制引用
孙平涛,董国昌,黎力乐,丁吉平,韩松财..热-流-固-化耦合下裂缝性泥页岩地层井壁失稳特征分析[J].辽宁石油化工大学学报,2025,45(4):36-46,11.基金项目
国家自然科学基金联合基金项目(U1762216) （U1762216）
四川省自然科学基金项目(2022NSFSC1227). （2022NSFSC1227）
