弹性参数各向异性对页岩井周应力的影响  

Effect of Anisotropy of Elastic Parameters of Shale Formation on Stress Distribution Around Wellbore

作　　者：曹文科[1] 邓金根[1] 蔚宝华[1] 刘伟[1] 李扬[1] 

机构地区：[1]中国石油大学(北京)油气资源与探测国家重点实验室,北京102249

出　　处：《西安石油大学学报（自然科学版）》2016年第5期27-35,42,共10页Journal of Xi’an Shiyou University（Natural Science Edition）

基　　金：国家自然科学基金(编号:U1262201);国家自然科学基金(编号:PRP/indep-4-1311)

摘　　要：为研究层理性页岩地层井周应力分布及其对井壁稳定性的影响,针对页岩力学参数的各向异性特点,建立了基于横观各向同性材料本构关系的弹性理论分析模型,运用该模型计算井周应力,并与各向同性材料下的应力分布进行对比,获取了页岩地层弹性参数各向异性对井周应力分布的影响规律,同时对井壁稳定状况进行了评估。研究表明:井周应力分布对弹性模量各向异性的敏感性强于泊松比各向异性,相同的弹性模量与泊松比各向异性影响下的井周应力分布形态具有相似性,但弹性模量与泊松比各向异性比的增减导致的井周应力增减变化相反,弹性参数各向异性对井壁破裂压力的影响远大于对坍塌压力的影响,显著地影响井眼近井壁地带的破裂压力。In order to analyze the stress distribution around the borehole in stratification shale and its influence on the stability of the borehole,a model for calculating the stress distribution around the borehole in stratification shale was established based on the anisotropic characteristics of shale mechanical parameters and the constitutive relations of transversely isotropic material,the influence law of the anisotropy of the elastic parameters of shale formation on the stress distribution around borehole is obtained by comparing the calculation result with the stress distribution around the borehole in transversely isotropic shale,and the stability of the borehole in the stratification shale was evaluated. It is shown that,the stress distribution around borehole is more sensitive to the anisotropy of Young＇s modulus than that of Poisson＇s ratio; the stress distribution form around borehole is similar under the same anisotropy degree of Young＇s modulus and Poisson＇s ratio,but the variation tendency of the stress distribution around borehole is opposite to the variation tendency of the anisotropy ratio of Young＇s modulus to Poisson＇s ratio; the influence of the anisotropy of elastic parameters on borehole fracture pressure is much greater than that on borehole collapse pressure,and the anisotropy of elastic parameters significantly influences the rock fracture pressure near wellbore.

关 键 词：井周 应力分布 横观各向同性页岩 井壁稳定 

分 类 号：TE21[石油与天然气工程—油气井工程]