高温高压含硫气井屏障部件失效概率分析

Failure Probability Analysis of Barrier Components in HTHP Sour Gas Wells

目前中外油气井定量风险评估普遍采用的WellMaster和OREDA的井屏障部件失效概率数据库对四川盆地高温高压含硫气井的准确性及适用性均较差。因此,为了针对四川盆地高温高压高含硫气井特点,根据各井屏障部件的质量、服役环境、测试结果和管理水平等分析,对井屏障部件实际服役条件下的失效概率计算方法进行研究,利用层次分析法将评价指标分为目标层、准则层、方案层3个层次,采用1-9标度法建立评价矩阵进行失效影响因素的加权权重计算,实现定性与定量方法的结合,准确地获取了不同井况条件和井屏障现状下的失效概率值。结果表明,基于层次分析法所建立的失效概率修正计算方法可以有效地结合各部件影响程度的已知数据,同时可对数据库的失效数据进行较为准确的修正。

At present,the WellMaster and Oreda database are widely used for quantitative risk assessment of well barrier component failure probability.However,the data in the databases are from offshore oil and gas wells,and the accuracy and applicability of them are poor for high-temperature and high-pressure sour gas wells in the Sichuan Basin,Southwest China.Therefore,according to the characteristics of high temperature,high pressure,and high sulfur gas wells in the Sichuan Basin,combined with the analysis of the quality,service environment,test results,and management level of barrier components of each well,a new calculation method of failure probability under the actual service conditions of well barrier components was proposed.The evaluation indexes could be divided into target layer,criterion layer,and scheme layer by using the analytic hierarchy process.The evaluation matrix was established by using 1-9 scale method,from which the weighted weight of failure influencing factors were calculated.Qualitative and quantitative methods were combined,and the failure probability values under different well conditions and well barrier status were accurately obtained.The results show that the failure probability correction calculation method based on analytic hierarchy process(AHP)can combine the known data of the influence degree of each component effectively,and correct the failure data of the database accurately.