页岩气井环空带压安全风险定量评价方法研究

Research on Safety Assessment Technology of Sustained Casing Pressure in Shale Gas

针对页岩气开发过程中井筒完整性失效引发的环空带压问题,开展了页岩气井井筒环空带压安全风险定量评估研究。基于模糊综合评判理论,充分考虑页岩气井的井筒实体屏障、流体屏障、运行管理等实际情况,建立了以环空压力、固井质量和地层完整性3个关键风险指标为依据的页岩气环空带压井安全风险评估方法,在某页岩气田进行了应用,对19口环空带压井的风险值和风险度进行了定量评估,并根据风险评价结果,从环空最大许可带压值确定、环空带压诊断、环空带压监测管理等方面给出了一套页岩气井环空带压安全管控推荐作法,研究成果为页岩气井的安全生产提供了重要的技术指导。

Aiming at the potential safety risks of wellbore annulus pressure caused by the integrity failure of the wellbore in the process of shale gas development,a safety risk assessment method for shale gas annulus compression wells is established.Based on the three key risk indicators of annulus pressure,cementing quality and formation integrity,this method considers the physical barrier,fluid barrier and operation management of shale gas wells based on fuzzy comprehensive evaluation theory.This method was applied to quantitative evaluation of the risk value and risk of 19 annulus pressure in a shale gas field.According to the results of risk assessment,a set of recommended practices for safety control of shale gas wells is presented from the aspects of determination of the maximum allowable value of annular pressure,diagnosis,monitoring and management of annular pressure,which provides important technical guidance for the safe production of shale gas wells.