中国石油大学学报（自然科学版）2018，Vol.42Issue(3)：64-69,6.DOI:10.3969/j.issn.1673-5005.2018.03.008
变内压条件下井筒完整性的弹塑性分析
Elastoplastic analysis of wellbore integrity under varying internal casing pressure
摘要
Abstract
In order to study the wellbore integrity under varying internal casing pressure,casing,cement sheath and near well-bore rock formation were considered as elastoplastic materials. The failure modes of the wellbore include the formation of micro-fractures and circumferential tensile damage of the cement sheath. A finite element method was used to simulate the effect of different cement and formation parameters on wellbore integrity. The results show that the larger of the cement sheath elasticity modulus,the higher possibility for the micro-fractures and circumferential tensile damages to occur. As the cement Poisson's ratio decreases,the size of the micro-fracture increases and the circumferential tensile damage is more readily to occur. Howev-er,the influence of the cement Poisson's ratio is less than that of the cement elasticity modulus. The smaller of the formation e-lasticity modulus,the higher possibility for micro-fractures to appear with larger sizes,and more possible for the circumferential tensile damage to occur. The size of micro-fractures increases as the formation Poisson's ratio increases. The effect of formation Poisson's ratio is less than that of formation elasticity modulus,while the effect of Poisson's ratio on the circumferential tensile damage is not significant. The circumferential tensile damage can occur before the micro-fractures form.关键词
变内压/井筒完整性/弹塑性/微间隙/周向拉伸破坏Key words
internal casing pressure change/wellbore integrity/elastoplastic/micro-fracture/circumferential tensile damage分类
能源科技引用本文复制引用
郭辛阳,吴涌泉,步玉环,李强,郭胜来..变内压条件下井筒完整性的弹塑性分析[J].中国石油大学学报（自然科学版）,2018,42(3):64-69,6.基金项目
国家自然科学基金项目(51704325,51704321) （51704325,51704321）
国家"973"重点基础研究发展计划项目(2015CB251202) （2015CB251202）
中央高校基本科研业务费专项(18CX02103A) （18CX02103A）
