作者：闫怡飞1,2, 董卫1,2, 于本福2, 闫相祯2
作者单位：1. 中国石油大学(华东)机电工程学院, 山东 青岛 266580;
2. 中国石油大学油气CAE技术研究中心, 山东 青岛 266580
关键词：储气库;大尺寸套管;抗挤强度;修正模型
摘要：
根据大尺寸储气库套管受到外挤载荷时的受力及变形特点,通过室内全尺寸试验分析套管椭圆度、钢级、径厚比等因素对大尺寸储气库套管抗挤强度的影响,并利用试验数据对现有的套管抗挤计算公式进行修正。将套管变形分为弹性和塑性变形两个阶段,建立套管弹、塑性变形受力计算模型,利用能量平衡方程推导出套管抗挤强度计算公式,分析初始椭圆度、套管钢级和径厚比对大尺寸储气库套管抗挤强度的影响,将修正前后的计算结果与试验结果进行对比分析。研究结果表明:利用本文建立的套管挤毁受力模型能够很好地预测带有初始椭圆度的大尺寸储气库套管抗挤强度,计算公式简单、准确,适用于不同椭圆度、屈服强度和径厚比的套管抗挤强度计算,能够弥补现有大尺寸储气库套管规范的不足及缺失;套管的抗挤强度随着初始椭圆度和径厚比的增加而降低,随着套管钢级的增加而增加;内、外椭圆度对大尺寸储气库套管抗挤强度影响具有耦合作用,在制造过程中要严格控制椭圆度及其跳跃性,建议制订相应的储气库大尺寸套管内壁椭圆度控制规范以满足相应套管的需求。
Affect factor experimental analysis of large-size casing collapsing strength for underground gas storage
YAN Yifei1,2, DONG Wei1,2, YU Benfu2, YAN Xiangzhen2
1. College of Mechanical and Electronic Engineering, China University of Petroleum, Qingdao 266580, China;
2. Oil and Gas CAE Technology research Center, China University of Petroleum, Qingdao 266580, China
Abstract: A modified model has been built to calculate the collapsing strength of large-size casings for underground gas storage according to the force state and deformation behaviors of the casing under external pressure. Based on the experimental data, it was found that the effects of outer ovality variation and radius-thickness ratio stress on collapsing strength were analyzed via indoor full-scale test. The deformation in large-size casing was divided into the elastic stage and the plastic stage. An equation was hence deduced from a mechanics model to calculate the collapsing strength and the influence of initial ovality, yield stress and diameter-thickness ratio on the collapsing strength of casing was discussed as well. The calculation results of the modified and traditional model were compared with the test data. According to the test, it was found that the modified model established on experimental data can well predict the collapsing strength of large-size casings with different ovality, yield strengths and diameter-thickness ratios, and can make up the deficiency of a control standard for large-size casings with underground gas storage. The collapsing strength of the casing decreases as the initial ovality and diameter-thickness ratio increase, but increases with the steel grade of the casing. The inner diameter ovality of the casing is coupled with that outer one. The ovality and its jumping should be strictly controlled in production. Therefore, it is proposed to establish corresponding standards to control the inner diameter ovality of large-size casings.
Keywords: underground gas storage;large-size casing;collapse pressure;modified model
2015, 41(11): 12-15 收稿日期: 2015-02-20;收到修改稿日期: 2015-04-03
基金项目: 国家自然科学基金(51274231,51374228,U1262208);中国石油天然气集团公司重点实验室项目;(2014A-4214)
作者简介: 闫怡飞(1984-),男,山东东营市人,博士,研究方向为地下储气库注采井的安全问题。
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