基于流固耦合理论的泥页岩井壁稳定性分析  

Borehole Stability Analysis of Shale Wells Based on the Theory of Fluid-solid Coupling

作　　者：黄桃[1] 蒲晓林[1] 罗霄[1] 于浩[1] 徐生江 

机构地区：[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 [2]中石油新疆油田分公司工程技术研究院,新疆克拉玛依834000

出　　处：《石油天然气学报》2014年第10期117-121,126,共6页Journal of Oil and Gas Technology

基　　金：国家重点基础研究发展计划("973"计划)项目(2013CB228003);国家自然科学基金项目(51304169)

摘　　要：钻井过程中,水基钻井液的化学渗透作用会导致井壁失稳,这个过程是钻井液与活性泥页岩地层发生强烈的流固热化多物理场耦合的过程。基于岩石力学和渗流力学理论,运用Comsol Multiphysics多物理场耦合软件建立耦合作用下井壁周围应力渗流流固耦合偏微分方程模型,并基于有限单元法对模型进行了求解。研究结果表明:有渗透和无渗透的井周应力分布是不一样的,且维持井壁稳定的防塌钻井液密度是随着时间增大而增大;将地层看成多孔弹性模型分析,并将水化应力分析考虑进来,研究发现水化应力张量对井周应力分布的大小和方向取决定作用,研究的结果对实际钻井有理论指导意义。Chemical osmosis of water base drilling fluid in the process of drilling would cause sidewall instability.It was the process of strong fluid-solid thermalization and multiple physical field coupling between drilling fluid and active mud shale in formation.Based on the theory of rock mechanics and seepage mechanics,apartial differential equation model of fluid-solid coupling around borehole under the action of seepage was established with Comsol Multiphysics and multiple physical field coupling software,and the model was calculated with finite method.The results show that the circumferential stress distribution around well with permeability is different from that without permeability.And the density of borehole collapse prevention drilling fluid for stabilizing borehole increases with the time increases.The formation is taken as a porous elastic model for analysis,and the hydration stress is analyzed,the study shows that the hydration stress tensor plays a crucial role in determining the size and direction of the circumferential stress distribution.The results have theoretical significance of the actual drilling.

关 键 词：泥页岩 化学渗透 Comsol 流固耦合 

分 类 号：TE21[石油与天然气工程—油气井工程]