泥页岩多场耦合流变模型  

Multi-field Coupling Rheological Model of Shale

作　　者：王萍[1,2] 张燕明 吕杨[5] 梁凌云 崔云群[3,4] 屈展 刘利锋[3,4] 李树生 WANG Ping;ZHANG Yanming;LYU Yang;LIANG Lingyun;CUI Yunqun;QU Zhan;LIU Lifeng;LI Shusheng(College of Petroleum Engineering,Xi'an Shiyou University,Xi'an,Shaanxi 710065,China;Shaanxi Key Laboratory of Oil/Gas Well and Reservoir Seepage and Rock Mechanics,Xi'an,Shaanxi 710065,China;National Engineering Laboratory for Exploration and Development of Low-permeability Oil & Gas Fields,Xi'an,Shaanxi 710018,China;Research Institute of Oil and Gas Technology,Changqing Oilfield Company,Xi'an,Shaanxi 710018,China;No.5 Gas Production Plant,Changqing Oilfield Company,Xi'an,Shaanxi 710018,China)

机构地区：[1]西安石油大学石油工程学院,陕西西安710065 [2]陕西省油气井及储层渗流与岩石力学重点实验室,陕西西安710065 [3]低渗透油气田勘探开发国家工程实验室,陕西西安710018 [4]长庆油田分公司油气工艺研究院,陕西西安710018 [5]长庆油田分公司第五采气厂,陕西西安710018

出　　处：《西安石油大学学报（自然科学版）》2021年第3期50-57,共8页Journal of Xi’an Shiyou University（Natural Science Edition）

基　　金：国家自然科学基金项目(51974255、51674200);陕西省自然科学基础研究项目(2020JM-544)。

摘　　要：在泥页岩井壁稳定性分析中,考虑岩石的流变特性和初始微缺陷造成的损伤及其耦合发生过程中的演化扩展,以经典半透膜渗透理论和多孔介质有效应力原理为基础,建立了泥页岩岩石应力场、化学场与渗流场耦合作用下的流变分析模型,给出了泥页岩在力学与化学耦合下蠕变损伤的有限元分析格式,分析了其对应力场、孔隙压力、渗透率的影响。结果表明:井壁围岩蠕变损伤导致其变形具有明显的时效性和非线性特性,应力最大值不在井壁上,而是在近井壁地带,在井眼附近会形成应力集中,造成井眼破坏,导致井壁失稳;围岩孔隙压力随时间、距离的增长而增大后趋于平衡;岩石蠕变损伤发展引起渗透率先减小后增大,其演化率与岩石的裂缝扩展一致。The rheological properties of rock,the damage of rock caused by initial micro defects and the propagation evolution of micro defects are considered in the stability analysis of shale wellbore.The rheological model of shale under the coupling effect of stress field,chemical field and seepage field is established based on the classical semi-permeable membrane permeability theory and the effective stress principle of porous media.The finite element analysis format of creep damage of shale under mechanical and chemical coupling is given,and the influence of creep damage on stress field,pore pressure and permeability is analyzed.The results show that the creep damage of surrounding rock has obvious time effect and nonlinear characteristics,and the maximum stress is not on the well wall,but near the well wall.Stress concentration is formed near the wellbore,resulting in borehole damage and wellbore instability.The pore pressure of surrounding rock increases with the increase of time and distance,and then tends to equilibrium.The development of rock creep damage causes the permeability to decrease first and then increase,and its evolution law is consistent with the expansion of rock cracks.

关 键 词：泥页岩 多场耦合模型 流变分析 蠕变损伤 有限元计算 

分 类 号：TE21[石油与天然气工程—油气井工程]