石油学报 ›› 2010, Vol. 31 ›› Issue (1): 161-164.DOI: 10.7623/syxb201001031

• 石油工程 • 上一篇    下一篇

基于可靠性理论的套管失效风险评价方法

廖华林 1 管志川 1 闫振来 2 马广军 1,2   

  1. 1中国石油大学石油工程学院 山东东营 257061; 2中国石化胜利石油管理局钻井工艺研究院 山东东营 257017
  • 收稿日期:2009-02-22 修回日期:2009-06-24 出版日期:2010-01-25 发布日期:2010-05-21
  • 通讯作者: 廖华林

Assessment method of casing failure risk based on structure reliability theory

LIAO Hualin 1 GUAN Zhichuan 1 YAN Zhenlai 2 MA Guangjun 1,2   

  • Received:2009-02-22 Revised:2009-06-24 Online:2010-01-25 Published:2010-05-21
  • Contact: LIAO Hualin

摘要:

针对套管几何参数、力学性能和外载存在随机性的特点,对传统套管安全系数设计与评价方法不足之处进行了分析。根据结构可靠性理论,建立了套管抗外挤强度和抗内压强度的失效风险评价方法。采用Monte-Carlo随机抽样法,模拟出了套管强度的随机分布规律,得出了不同载荷条件下套管失效概率以及安全系数与套管失效概率之间的对应关系。研究表明,基于可靠性理论建立的套管失效风险评价方法,可对套管的安全可靠度进行定量评价。对于不同的套管类型和外载条件,安全系数相等,而失效概率并不相同。计算出的失效概率评价指标,可为传统安全系数的选取和外载条件不确定性情况下套管设计与评价提供依据。

关键词: 套管强度, 可靠性理论, Monte-Carlo方法, 失效概率, 安全系数

Abstract:

The geometric parameters, mechanical properties and external loading of casing have the stochastic property. The deficiency of the traditional method for design of casing safety factors was analyzed. An evaluation approach of casing reliability resistant to casing collapse and burst strength was established according to the structural reliability theory. The distribution regularities of casing strength were simulated by the Monte-Carlo random sampling method. The probabilities of casing failure and the correspondence with safety factors under different loading conditions were discussed. The study showed that the assessment method of casing failure risk could be used to quantitatively evaluate casing reliability. For the different types of casings and loadings, casing failure probabilities may not be equivalent under the same safety factors. The failure probability target level calculated by the established reliability method could provide foundations for selection of safety factors as well as design and evaluation of casing under uncertainty loading conditions.

Key words: casing strength, reliability theory, Monte-Carlo method, failure probability, safety factor