中国石油大学学报（自然科学版）2024，Vol.48Issue(3)：91-100,10.DOI:10.3969/j.issn.1673-5005.2024.03.010
循环剪切作用下含可燃冰砂土-开采井界面强度弱化细观机制
Meso-mechanism of weakening characteristics of interface between gas hydrate-bearing sand and mining well under cyclic shear
摘要
Abstract
Rock formation with gas hydrate-bearing sands exhibits features of shallow burial,unformed rock and low strength.The weakening characteristic of the interface between gas hydrate-bearing sand and mining well under wave cyclic loading are significant and can directly affect the wellhead stability.In this study,the cyclic shear mechanical properties of the interface between gas hydrate-bearing sands and mining well were investigated based on a discrete element method(DEM).By setting the wellbore motion caused by wave cyclic loading,the macroscopic weakening mechanism of the interface was revealed from a mesoscopic perspective.The results show that the gas hydrate-bearing sand can cause a significant strength weakening and shear dilation at the interface between gas hydrate-bearing sands and mining well,and the higher the gas hydrate saturation,the more significant the weakening and shear dilation.The reason is that the near-wellbore gas hydrate-bearing sands can form a cementation failure zone under cyclic shear,where the cementation of most particles could be failed,while a few gas hydrate particles that might not failed to cement could form larger size clusters with neighboring particles,but these particles and clusters tumble and move complexly which cannot adequately transfer loads,resulting in strength weakening and shear dilation.Increase of both normal stress and shear amplitude can aggravate the cementation failure of the near-wellbore gas hy-drate particles,and the strength weakening phenomenon can be more severe.关键词
含可燃冰砂土-开采井界面/循环剪切/界面弱化/胶结作用/离散元Key words
interface between gas hydrate-bearing sand and mining well/cyclic shear/interface weakening/cementation/discrete element method分类
能源科技引用本文复制引用
张玉,侯劲宇,栾雅琳,陶子卓,李建威..循环剪切作用下含可燃冰砂土-开采井界面强度弱化细观机制[J].中国石油大学学报（自然科学版）,2024,48(3):91-100,10.基金项目
国家自然科学基金项目(51890914,52179119) （51890914,52179119）
